Feature: Don't prompt on each file when invoking git merge/diff tools

Normally git prompts on each file that needs to be merged/diffed. This setting
suppresses that.

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Change-Id:     I3de17554715520290f15642c6c79f780abf6f2de
Signed-off-by: Jeff Felchner <accounts+git@thekompanee.com>
Bugfix: Comment all lines in the custom git commit template

The previous assumption was that everyone would be using our git hook template
directory in all projects, but that's obviously not the case.  So the problem is
that a lot of the lines in the template were uncommented and without the hooks
installed, they never had the comments added so that they wouldn't show up in
the commit messages.

The solution was to comment _all_ the lines by _default_.  Then, when the hooks
are run, they _uncomment_ certain lines as appropriate.

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Change-Id:     I3dbbe8d70be42d87dc5aa79273fb70bfbceec55f
Signed-off-by: Jeff Felchner <accounts+git@thekompanee.com>
Feature: Add a blank line to the beginning of the git commit template

When you want to write just a quick git commit message, you typically want to
just start writing at the beginning of the file without worrying about clicking
elsewhere to start typing.

Adding a blank line to the top of the commit message template allows you to do
this while simultaneously still allowing users to jump to each section just as
easily as before.

It looks _slightly_ uglier, but not too bad.

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Change-Id:     Ic7c01ef05e7545d49717e15dd9842e5a0214b051
Signed-off-by: Jeff Felchner <accounts+git@thekompanee.com>
Bugfix: Silence errors from Gerrit func when commit message is empty

Previously, if the commit message was empty, when it tried to generate the
Gerrit change ID, it would complain, we know that this will happen so we just
silence the errors to `/dev/null`.

This may potentially cause errors which we _want_ to be displayed to be silenced
as well, but the functionality is so small, this is unlikely.

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Change-Id:     I05613c02b4d985f66478efef4436ac5509e4793c
Signed-off-by: Jeff Felchner <accounts+git@thekompanee.com>
Docs: Update example in commit message template to reflect our changes

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Change-Id:     Idd1b44c92d87e17de6da5e82717105a5dd7cf02d
Signed-off-by: Jeff Felchner <accounts+git@thekompanee.com>