Merge branch 'jc/name-branch'

Merge branch 'jc/name-branch'

* jc/name-branch:
  Don't permit ref/branch names to end with ".lock"
  check_ref_format(): tighten refname rules
  strbuf_check_branch_ref(): a helper to check a refname for a branch
  Fix branch -m @{-1} newname
  check-ref-format --branch: give Porcelain a way to grok branch shorthand
  strbuf_branchname(): a wrapper for branch name shorthands
  Rename interpret/substitute nth_last_branch functions

Conflicts:
	Documentation/git-check-ref-format.txt