Adding git-ensconfig

This extra command provides a way to set/get/unset current user's identity if the actual repos owner is a shared user
Hooks to force user to provide a committer id
When a repos is cloned, default hooks get enabled

'git ensembl --clone' places symlinks of default hooks to the repos .git/hooks dir
Adding --hooks option to enable/disable hooks
Merge branch 'feature/force_committer_id'

Conflicts:
	bin/git-ensembl