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/build.sh

@@ -0,0 +1,42 @@
+echo "Build Artemis executable.."
+
+rm -rf output
+
+mkdir output
+mkdir output/artemis
+
+pyinstaller Artemis.spec
+
+mv -v ./dist/Artemis ./output/Artemis
+rm -rfv dist build
+
+echo "Build _ArtemisUpdater.."
+
+pyinstaller updater.spec
+
+mv -v ./dist/_ArtemisUpdater ./output/_ArtemisUpdater
+rm -rfv dist build
+
+echo "Create single archives"
+cd output
+
+cp -r ../../../src/themes artemis/themes
+rm -f artemis/themes/__current_theme
+cp Artemis artemis/Artemis
+cp _ArtemisUpdater artemis/_ArtemisUpdater
+
+tar -czvf Artemis_linux.tar.gz Artemis -C artemis themes
+tar -czvf _ArtemisUpdater_linux.tar.gz ./_ArtemisUpdater
+
+echo "Create full archive for website"
+
+cp ../artemis3.svg artemis
+cp ../create_shortcut.sh artemis
+
+tar -czvf ArtemisWebDownlaod_linux.tar.gz artemis
+
+echo "Get size and sha256"
+python ../../__get_hash_code.py Artemis_linux.tar.gz _ArtemisUpdater_linux.tar.gz ArtemisWebDownlaod_linux.tar.gz
+
+cd ..
+echo "Done."