[StatusBar] Don't decode url of hovered link

Workarounds #1095
[WebView] Edit isValidUrl method. All non-empty urls are valid now.

Fixes #1099
[UrlCompleter] Don't show same urls multiple times

Closes #1096
[Code] Add/Edit some comments
[Bookmarks] Fixed drag&drop moving folders into bookmarks toolbar

Closes #1097
[Preferences] Move "Add .co.uk by pressing ALT" option under Keyboard Shortcuts

This option adds local domain (not necessarily .co.uk) by pressing ALT

Closes #1047
[Sessions] Last 2 sessions are now backuped in profile directory.

Closes #1100
[Translations] Pulled app translations from Transifex
Added Qt translations for new languages
Serbian translations update
[Translations] Pulled plugins translations from Transifex
[Scripts] Added new generate-qmake-plugins-translations script

Also removed old unused scripts
[Translations] Pulled all plugins translations from Transifex

*Passwords and StatusBarIcons were missing
Merge branch 'master' into ComboTabBar