Enhanced mdw.git.autopull

[donaldoakes]

(The name above makes more sense than our current mdw.git.auto.pull).

End-user asset management in MDWHub is not as friendly as it could be because of the potential for Git conflicts when multiple users are editing assets through the web. A good way to solve this would be to extend autopull so that it automatically keeps the instance up-to-date with Git by pulling periodically (maybe in the AssetImportMonitor thread).

[jbrojdeCTL]

mdw.git.auto.pull will no longer try to do a pull upon startup. Instead, the AssetImportMonitor will automatically do a git pull whenever it detects there's a new commit on the remote repo that it can pull.