Fix a bug in the *.spec files and also apply the following major changes:

- Add support for adding the base folder to PATH.
- Only display one pop up window at a time in order to avoid confusion.
- Add automatic updates feature:
	- Windows and Linux versions will be shipped with an updater program used to
	  update both Artemis and the updater itself.
	- MacOs versions will not have the updater. Instead the user will be asked
	  to download the new software version (if present) via browser.

src/updatescontroller.py

@@ -0,0 +1,141 @@
+import subprocess as sp
+import webbrowser
+from PyQt5.QtCore import QObject, pyqtSlot, QProcess
+from PyQt5.QtWidgets import QMessageBox, qApp
+from constants import Constants, Messages, DownloadTarget
+from downloadtargetfactory import get_download_target
+from utilities import pop_up
+from os_utilities import IS_MAC
+from executable_utilities import IS_BINARY
+from threads import UpdatesControllerThread
+from versioncontroller import VersionController
+
+
+class UpdatesController(QObject):
+
+    def __init__(self, current_version, owner):
+        super().__init__()
+        self._owner = owner
+        self._download_window = self._owner.download_window
+        self._current_version = current_version
+        self.version_controller = VersionController()
+        self._updates_thread = UpdatesControllerThread(self.version_controller)
+        self._updates_thread.on_success.connect(self._startup_updates_check)
+
+    def start(self):
+        """Start the thread."""
+        if IS_BINARY:
+            self._updates_thread.start()
+
+    @pyqtSlot()
+    def start_verify_software_version(self):
+        if not IS_BINARY:
+            pop_up(
+                self._owner,
+                title=Messages.FEATURE_NOT_AVAILABLE,
+                text=Messages.SCRIPT_NOT_UPDATE
+            ).show()
+            return
+        if not self._download_window.isVisible():
+            self._updates_thread.start()
+
+    @pyqtSlot(bool)
+    def _verify_software_version(self, success):
+        """Verify if there is a new software version.
+
+        Otherwise notify the user that the software is up to date."""
+        if not self._download_window.isVisible():
+            if success:
+                new_version_found = self._check_new_version()
+                if not new_version_found:
+                    pop_up(
+                        self._owner,
+                        title=Messages.UP_TO_DATE,
+                        text=Messages.UP_TO_DATE_MSG
+                    ).show()
+            else:
+                pop_up(
+                    self._owner,
+                    title=Messages.NO_CONNECTION,
+                    text=Messages.NO_CONNECTION_MSG
+                ).show()
+
+    @pyqtSlot(bool)
+    def _startup_updates_check(self, success):
+        self._updates_thread.on_success.disconnect()
+        self._updates_thread.on_success.connect(self._verify_software_version)
+        if success:
+            if not self._check_new_version():
+                # Check for a new version of the updater only if Artemis is up to date.
+                self._check_updater_version()
+
+    def _check_new_version(self):
+        """Check whether there is a new software version available.
+
+        Does something only if the running program is a compiled version."""
+        if not IS_BINARY:
+            return None
+        latest_version = self.version_controller.software.version
+        if latest_version is None:
+            return False
+        if latest_version == self._current_version:
+            return False
+        answer = pop_up(
+            self._owner,
+            title=Messages.NEW_VERSION_AVAILABLE,
+            text=Messages.NEW_VERSION_MSG(latest_version),
+            informative_text=Messages.DOWNLOAD_SUGG_MSG,
+            is_question=True,
+        ).exec()
+        if answer == QMessageBox.Yes:
+            if IS_MAC:
+                webbrowser.open(self.version_controller.software.url)
+            else:
+                updater = QProcess()
+                command = Constants.UPDATER_SOFTWARE + " " + \
+                    self.version_controller.software.url + \
+                    " " + self.version_controller.software.hash_code + \
+                    " " + str(self.version_controller.software.size)
+                try:
+                    updater.startDetached(command)
+                except BaseException:
+                    pass
+                else:
+                    qApp.quit()
+        return True
+
+    def _check_updater_version(self):
+        """Check is a new version of the updater is available.
+
+        If so, ask to download the new version.
+        If the software is not a compiled version, the function is a NOP."""
+        if not IS_BINARY or IS_MAC:
+            return
+        latest_updater_version = self.version_controller.updater.version
+        try:
+            with sp.Popen(
+                [Constants.UPDATER_SOFTWARE, "--version"],
+                encoding="UTF-8",
+                stdout=sp.PIPE,
+                stderr=sp.STDOUT,
+                stdin=sp.DEVNULL  # Needed to avoid OsError: [WinError 6] The handle is invalid.
+            ) as proc:
+                updater_version = proc.stdout.read().rstrip("\r\n")  # Strip any possible newline, to be sure.
+        except Exception:
+            updater_version = latest_updater_version
+        if latest_updater_version is None:
+            return
+        if updater_version != latest_updater_version:
+            answer = pop_up(
+                self._owner,
+                title=Messages.UPDATES_AVAILABALE,
+                text=Messages.UPDATES_MSG,
+                is_question=True,
+            ).exec()
+            if answer == QMessageBox.Yes:
+                self._download_window.activate(
+                    get_download_target(
+                        DownloadTarget.UPDATER,
+                        self.version_controller.updater
+                    )
+                )