Switched to JGit
Switched to JGit

Switched from Git to JGit (a Java implementation of Git) in order to
make the build more portable. Depending on Git was a problem especially
on Windows, where PATH is a pain to edit.

CIRDLES/Topsoil,johnzeringue/Topsoil,johnzeringue/Topsoil,emilycoleman/Topsoil,CIRDLES/Topsoil,emilycoleman/Topsoil