Leave repository in clean state after commit

[hauleth]

This will clean repository state after commit removing all @commit from diff.

[jryio]

Oh this is great! Let run some tests quickly.

Thank you so much for this! Leaving the repository littered with changes to stage was not the best.

[jryio]

@hauleth One issue I am having is that once a commit is complete, the git commit command hangs for 100+ seconds.

That is, once you write your commit and close the editor, the process does not quit immediately after completing the post-commit hook with the added changes from this PR.

Here is the output I got after letting git commit run for about 2 minutes.
Side note: I titled my commit Another test, do not add

.git/hooks/prepare-commit-msg: fork: Resource temporarily unavailable
.git/hooks/prepare-commit-msg: fork: Resource temporarily unavailable
.git/hooks/prepare-commit-msg: fork: Resource temporarily unavailable
.git/hooks/prepare-commit-msg: fork: Resource temporarily unavailable
.git/hooks/prepare-commit-msg: fork: Resource temporarily unavailable
.git/hooks/prepare-commit-msg: fork: Resource temporarily unavailable
.git/hooks/prepare-commit-msg: fork: Resource temporarily unavailable
[hauleth-amend 53cf509] Another test, do not add
Date: Fri Jan 15 20:56:46 2016 -0800
4 files changed, 23 insertions(+), 21 deletions(-)
[hauleth-amend 53cf509] Another test, do not add
Date: Fri Jan 15 20:56:46 2016 -0800
4 files changed, 23 insertions(+), 21 deletions(-)
[hauleth-amend 00028c9] Another test, do not add
Date: Fri Jan 15 20:56:46 2016 -0800
4 files changed, 23 insertions(+), 21 deletions(-)
[hauleth-amend 00028c9] Another test, do not add
Date: Fri Jan 15 20:56:46 2016 -0800
# I cut out about 1,000 repetitions
4 files changed, 23 insertions(+), 21 deletions(-)
[hauleth-amend 94da598] Another test, do not add
Date: Fri Jan 15 20:56:46 2016 -0800
4 files changed, 23 insertions(+), 21 deletions(-)
[hauleth-amend 03f8d6b] Another test, do not add
Date: Fri Jan 15 20:56:46 2016 -0800
4 files changed, 23 insertions(+), 21 deletions(-)
[hauleth-amend 4c8dd4b] Another test, do not add
1 file changed, 2 insertions(+)

This might be caused by how Bash implements the @ operator for lists when using "${ADDED_FILES[@]}" - I will look into this.

For reference I am running a zsh terminal session, using Git version 2.6.3 and using Vim as my commit editor.