LatinIME: Customize features for regional package.

- Customize auto correction type of input method LatinIME.
- Make the button in the lower right corner of the keyboard to be Enter
  button in MMS.

Change-Id: I6eccf7b78258765b52ffa28c9e43fa771e6e0799
LatinIME: Reginal requirement for RTL

Convert left/right layout properties to start/end properties.

Change-Id: Ib7121d4aeb550bf2c88af764733a6a2b2c114782