Merge branch 'master' of git://github.com/rikettsie/erlexec into rikettsie-master

Also added support for environment tuples in the form
{env, [{Var::string(), Value::string()}]}

Conflicts:
	c_src/exec.cpp
Fixed doc target
Merge branch 'master' of git://github.com/saleyn/erlexec

Conflicts:
	c_src/exec.cpp
Merge branch 'master' into make_mac_compile_hack

Conflicts:
	c_src/exec.cpp
Re-added Mac hacks - these didn't merge cleanly when updating from upstream.