Enhance Git Command Detection Flexibility

[jimbrig]

See the bottom of #38 for details:

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Note that during my inspection of these test files I found some other potential areas of improvement also.

For example, on my machine, I have two git executables on my PATH and therefore the statement $git = (Get-Command git -CommandType Application -ErrorAction SilentlyContinue) would return git.exe git.exe instead of just git.exe causing the $thisCommit = & $git log --decorate --oneline HEAD~1..HEAD expression to fail:

I simply addressed this issue by changing $git = (Get-Command git -CommandType Application -ErrorAction SilentlyContinue) to $git = (Get-Command git -CommandType Application -ErrorAction SilentlyContinue)[0] to ensure it always is singular.

Now I'm in the clear!

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Solution to be provided in PR for both issues if you want them (if not that's fine also!).