Merge branch 'maint'

* maint:
  Document -g (--walk-reflogs) option of git-log
  sscanf/strtoul: parse integers robustly
  git-blame: Fix overrun in fake_working_tree_commit()
  [PATCH] Improve look-and-feel of the gitk tool.
  [PATCH] Teach gitk to use the user-defined UI font everywhere.