Implement "git commit" functionality

[kencasimiro]

Implemented git commit.

For some reason GitPython's git commit caused tkinter window to crash. Screenshot of error message:

Rather than spending a lot of time debugging the code in tkinter and such, I resorted to do git commit through subprocesses.

Example of git commit - success:

Example of git commit - nothing to commit:

[air-wickvu]

tested on my end and is working. will go ahead and merge.