prebuilt: add LatinIME_slim
          /system partition is too small currently (~235 mB)
          34 mB -> 6.7 mB

//TODO: find a way to fit ROM into /system partition
        without removing languages!!!

//TODO: include langauges in LatinIME respecting
        PRODUCT_LOCALES

Change-Id: I17a35ca84ed4dd88bfe37a7c75b166ad1be61373