Ctrl activation: Opens url in new tab
Shift activation: Opens url in new window
Closes#1245
Bookmarks: Update visit count also from location completer
BookmarkItem: Added new method updateVisitCount
New format is compatible with Chromium's Bookmarks file.
It will support everything as the current backend +
* multi-level bookmarks
* bookmark description
* bookmark keyword
* remember expanded state (for folders)
NOTE: It is NOT yet complete. There is a LOT of work still needed.
Only bookmarks loading + saving and internal tree representation is
done.