Call AIFilePicker::create() instead of new AIFilePicker.
Renamed deleteMe() to kill() and bs_deleted to bs_killed.
Only default to auto destruct when created with create(true),
otherwise kill() has to be called explicitely.
Also upgrade the file picker filters with the new extensions found
in the orginal file picker code of Singularity.
Also improve AIFilePicker a bit: added hasFilename() and now
deleting the statemachine automatically by default: it's no longer
needed to call deleteMe from the callback.
