Display Git Build Number and Date for Unstable Branch

If running unstable, Mh will now try and determine a build number and modification date by calling git commands.
Merge remote-tracking branch 'krkeegan/build_number'
Merge pull request #304 from krkeegan/build_number

Display Git Build Number and Date for Unstable Branch. Tested against both stable and unstable branch.
Merge branch 'master' of github.com:hollie/misterhouse