Remove uncalled functions

- __git_local_references
- __git_deleted_files
- __git_ignored_cached_files
- __git_unmerged_files
- __git_killed_files
- __git_repositories
- __git_guard_diff-stat-width
- __git_stages
cleanup: remove superfluous functions

- __git_references
- __git_commitishs
- __git_revisions
- __git_treeishs
- __git_objects