* More local variable cleanup.

* Added provisions for js.branch_limit for the newer Synchronet CVS revisions,
  provision for the old branch.limit will disappear later.
* Fixed the "unmode" bug where modes would be set -oooo (etc) on a PART then
  SJOIN.  We were using SJOIN inappropriately for users joining a channel
  that already exists, a 5-parameter SJOIN is for new channels and
  synchronization only.