Bookmarks: Added BookmarksTree class that manages all bookmark's view types.
-BookmarksSidebar, BookmarksWidget,BookmarksManager and ... use BookmarksTree
-Added 'New Folder...'
-Fixed some issues
Bookmarks: Don't allow creating folder with translated name of "bookmarksToolbar", "bookmarksMenu" or "unsorted"!
Added 'Expand All' and 'Collapse All' buttons to bookmarks manager.
Merge pull request #701 from sys9kdr/master

Update Japanese Language File
Serbian translation updates
Move connectons from .ui to .cpp
Bookmarks: when deleting lastFolder set it to default.
Add QupZilla* pointer to PopupWindow class
Merge branch 'bookmarks_work' of git://github.com/srazi/qupzilla into srazi-master
Updated German translation

Reviewed by J. Hooverman
Coding style
[Qt5] Ported all plugins to Qt5 plugin system
[Fix] Saving '+' character in passwords/usernames

Closes #703
RecoveryWidget: Switch positions of buttons.

Buttons now match Firefox.
Start new session is first and then Restore.
Fixed opening popup windows with QtWebKit 2.3

It now correctly opens new tab / popup window
according to arguments in window.open call.
File scheme handler: Sorting files case insensitive.
Fix possible crash on startup.

Don't calculate space for tab if the available
space is negative.
Ask user to allow site to use notifications/geolocation.

With option to remmber the choice for page.
Removed USE_QTWEBKIT_2_2 build variable.

It will now be automatically detected.
It assume that if you are building with Qt 4.8 and higher,
you have QtWebKit 2.2 and higher.
[Windows] fixed: open folder and select downloaded file (using ShellExecute for run explorer).
-Now it covers all possible situations (e.g. path with spaces, file without extention, ...)