Generate A-Z menus in the tagtree
this adds a new command %byfirstletter
%byfirstletter "custom_track" "Track A to Z" "title"
^ command ^menu name ^menu title ^subitem
need a better name for subitem btw..
this patch also allows us to tell when we are in the BFL menu
by checking customaction == ONPLAY_CUSTOMACTION_FIRSTLETTER
we then enable spelling of the letters in the menu
it spells Numeric too but that shouldn't matter with the upcoming voice patch
Change-Id: I59815f697a4ef84a8cb540783b620d15f6670e00