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.

spec_files/Linux/updater.spec

@@ -0,0 +1,51 @@
+# -*- mode: python ; coding: utf-8 -*-
+
+import os
+
+
+BASE_FOLDER = "../../src/"
+block_cipher = None
+
+data_file = [
+    (os.path.join(BASE_FOLDER, "download_db_window.ui"), "."),
+    (os.path.join(BASE_FOLDER, "download_window.py"), "."),
+    (os.path.join(BASE_FOLDER, "utilities.py"), "."),
+    (os.path.join(BASE_FOLDER, "versioncontroller.py"), "."),
+    (os.path.join(BASE_FOLDER, "downloadtargetfactory.py"), "."),
+    (os.path.join(BASE_FOLDER, "executable_utilities.py"), "."),
+    (os.path.join(BASE_FOLDER, "os_utilities.py"), "."),
+    (os.path.join(BASE_FOLDER, "web_utilities.py"), "."),
+    (os.path.join(BASE_FOLDER, "constants.py"), "."),
+    (os.path.join(BASE_FOLDER, "threads.py"), "."),
+    (os.path.join(BASE_FOLDER, "default_imgs_rc.py"), "."),
+    (os.path.join(BASE_FOLDER, "cacert.pem"), "."),
+]
+a = Analysis([os.path.join(BASE_FOLDER, 'updater.py')],  # noqa: 821
+             pathex=[os.getcwd()],
+             binaries=[],
+             datas=data_file,
+             hiddenimports=[],
+             hookspath=[],
+             runtime_hooks=[],
+             excludes=[],
+             win_no_prefer_redirects=False,
+             win_private_assemblies=False,
+             cipher=block_cipher,
+             noarchive=False)
+pyz = PYZ(a.pure,  # noqa: 821
+          a.zipped_data,
+          cipher=block_cipher)
+exe = EXE(pyz,  # noqa: 821
+          a.scripts,
+          a.binaries,
+          a.zipfiles,
+          a.datas,
+          [],
+          name='_ArtemisUpdater',
+          debug=False,
+          bootloader_ignore_signals=False,
+          strip=False,
+          upx=True,
+          runtime_tmpdir=None,
+          console=False,
+          icon='Artemis3.ico')