Merge live hacks from r83992 to trunk, after cleaning some things up.

Merge live hacks from r83992 to trunk, after cleaning some things up.

* Wait for slaves after every thousand rows rather than after processing every batch. r83992 had 1000 hard-coded, I put it in SYNC_INTERVAL
* Set $lb->waitTimeout(100000). I have no idea why, but it was in the live hack. Maybe Tim or Domas could enlighten me
* Use a STRAIGHT JOIN for the query on categorylinks and page because MySQL appears to want to join the tables the wrong way around
* Use cl_collation='previousValue' rather than cl_collation!='newValue' if possible. This was originally a dirty live hack, but I re-implemented it nicely with a --previous-collation command line option
* Print a status update both before and after the SELECT query. This allows the user to notice when the SELECT queries are getting increasingly slower, which is an indication you may want to set --previous-collation