Initial commit of NaCl VM. Currently only implemented for the server.
Merge branch 'engine-upgrade' of github.com:Unvanquished/Unvanquished into nacl

Conflicts:
	src/engine/qcommon/vm_traps.h
Tell travis to use g++ 4.7.
Cmd: move cvar expansion to the command queue
Make travis stop complaining about every failed build.
Cmd: Rename a few functions

"command text" refers to a text containing several commands
"command" refers to a single command
Cmd: add StartsOfCommands
Fix #includes in src/shared.
Allow iterator usage of class Args, e.g. for (auto c : arglist).

Note that the iterator skips the command
You can get one which includes the command by using beginWithCommand().
Convenience return-original-string operator.
Escape the substituted cvar value.
Cmd: try to use more move semantics
Cmd: Remove the need for Cmd::Init()
Cmd: Rename a bunch of functions
Cmd: Remove Cmd::Args::Iterator

It seems that it will have almost no use (which command
iterates over all its arguments starting from 1? /buy /sell and that's
all).
Cmd: Change the way static commands are handled
Cmd: implement /list<Subsystem>Cmds
Implement Args::GetArgs.
Mark Args::GetArgs() as inline. (Fixes build error.)
Args::operator[] for access as if array. (Uses Argv(int).)