Improved features for git-hack
Allow autocompletion of git branches for all Git commands

This is safer. The old way prevented autocompletion for normal
Git commands.
Improved features for git-town
resolves #199: command list architecture
Add missing feature specs for git ship
Missing feature specs for git kill
Improved features for git-extract
Merge branch 'master' into kg-improve-features-ship

Conflicts:
	features/git-ship/current_branch/pull_feature_branch_conflict.feature
	features/git-ship/supplied_branch/pull_feature_branch_conflict_with_open_changes.feature