Add git-salt module.

Add an initial communication between CDE and git-nacl port (`git-salt`).

1) This enables a `git-clone` powered by nacl behind a flag.
2) This is still a work in progress, and lot of things may be broken.
3) Some debug logs are left intentionally, will be cleaned in future.

This and the isRelease vars are global here, is that the intention?  If so it seems odd for them to be defined in this library.