[Bug 844717] - [Keyboard] Add Thai keyboard layout 

add thai layout for thai speak people

Continue from https://github.com/mozilla-b2g/gaia/pull/12239 but change layout to "Kedmanee"
see kedmanee layout 
http://en.wikipedia.org/wiki/File:800px-KB_Thai_Kedmanee.png
to test please build with GAIA_KEYBOARD_LAYOUTS=en,th make 
Work fine on Nexus4

@Veer66 @arky