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/themes/elegant_dark/elegant_dark.qss

@@ -404,4 +404,4 @@ QScrollBar::add-line:horizontal, QScrollBar::sub-line:horizontal,
 QScrollBar::add-line:vertical, QScrollBar::sub-line:vertical {
       border: none;
       background: none;
-}
+}