add [MappableControls] for translate, and some pickup and trims

"Language" had been moved to [Developer], see https://github.com/hrydgard/ppsspp/pull/3502
All "OK" and "Cancel" words are read from [Dialog] now. see https://github.com/hrydgard/ppsspp/pull/3518
Pick up missing string "Home", see https://github.com/hrydgard/ppsspp/blob/master/UI/MainScreen.cpp#L367
Add [MappableControls] for control mapping, see https://github.com/hrydgard/ppsspp/commit/f47c6d534d3151dada2a6220148ac2c053d97e47
All "OK" and "Cancel" words are read from [Dialog] now. see https://github.com/hrydgard/ppsspp/pull/3518
Merge pull request #149 from wuspring/en-US

add [MappableControls] for translate, and some pickup and trims