Fix Resource::Prune segfaulting
Build-depend on NaCl build env. package and use when available.

This package is, essentially, one of the cut-down NaCl SDK tarballs (either
i386 or amd64) prepared by Amanieu d'Antras.
Depend on unv-nacl-runtime; install/symlink the required binaries.
Send the  VM area portal changes to the engine.

The engine sends this state to the client. It caused a bug
where you wouldn't see what is behind a door before you stepped
through it.
Fix TTY client
Remove dead functions from the renderer
Remove some dead functions from cm client server and qcommon
Remove unused Sys_ListFiles functions
Fix invalid condition in tesla generator think
Merge branch 'master' into librocket

Conflicts:
	src/engine/qcommon/common.cpp