[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
https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-ash4/t1/1546241_781069895240730_992564772_n.jpg
https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-ash3/t1/1621888_781069918574061_209114634_n.jpg

@Veer66 @arky