Adds new features to truecrypt addon.

Added:
 - Support for key files - creation, mounting, adding, changing and
removing
 - Support for hidden volumes - mounting with hidden volume protection,
creation of container with hidden volume
 - Possibility to mount volumes at start up
 - Easier mounting of partition through guide -> mounting by drive id so
it is persistent when different drives are connected
 - Reason why some items are locked
 - Detection of mount point being in use by other mounted volumes
 - Mounting files without storing paths and mount points
 - Added a little bit of color in the menu
 - Possibility to use secondary shell script (development or testing)
 - New settings
 - Added strings.po language file, strings.xml is still kept
 
 
 Changed:
  - Debugging mode can only be turned on the XBMC debugging settings,
errors are always written in the log  
  - shell script has been rewritten to provide better flexibility