Update ng client code to 0.9.1.

Basically a copy of 'ng.c' from
https://github.com/martylamb/nailgun/blob/nailgun-all-0.9.1/nailgun-client/ng.c
Just changing the 'main' function to nailgunClientMain.
Update version to 1.0.16.
Instead of passing exitcode, exit with 1.

This should allow Guard to continue on even when specs fail.