Lingua Gettext, File++, GF7 compat

- unneccessary main calls on NaCl converted to normal code where pepper_26
  allows that with help of pp::MessageLoop
- ozCore
  * Set, Map, Hash*: contains(), index() and find() accept arbitrary type
    that can be compared to the key type
  * File: internal native* functions, initial custom VFS support
  * Gettext catalogue merging fixed
- common
  * Lingua ported to Gettext
- ozEngine & client
  * Shader only uses 4 sampler units