Make update_autogen handle loaddefs-like files as well.

Make update_autogen handle loaddefs-like files as well.

* autogen/update_autogen: (usage): Add -l, -C.
(clean, ldefs_flag, ldefs_in, ldefs_out): New variables.
With -l, check status of lisp/ as well.
With -C, clean before building.
(autoreconf): Only pass -f in the `clean' case.
(commit): New function.

* lisp/Makefile.in (AUTOGEN_VCS): New variable.
(autoloads): Use $AUTOGEN_VCS.

* .bzrignore: Tighten up ignore patterns (for autogen/).