PhysFS port++ => main calls++

- OZ_MAIN_CALL removed, NaCl doesn't work currently
- ozCore
  * File
    + ls(): thread-safe for POSIX, implemented for pepper_27 (not working yet)
    + mountLocal() got append parameter
- ozEngine
  * MainCall class, lambda functions are used for main thread callbacks
- client
  * NaCl: game archive reading progress on PhysFS mounting
- ports
  * PhysicsFS uses blocking calls, does not cache archives any more