[Code Cleanup] Applet code cleanup

Cleanup includes:

- Remove trailing whitespaces
- Replace tabs with spaces
- Don't use try/catch in _init as applet manager already does that
- Proper use of ";' and ","

Certain applets have pull requests pending and are not included in cleanup.
These include:

- Window list
- Show Desktop
- Menu
- Notifications

Diff (ignore-all-space): http://pastebin.com/Bh3JeZMn