Core titleCache doesn't do what I expect it to do, issuing
Title::newFromId( 1 ) mulitple times would issue multiple
idential queries to the database. It doesn't return what's
already in the cache.
The goal of this patch is to batch load titles via newFromIDs,
and save the number of mysql queries
Change-Id: I8fe767ac2669e67bdf7d17eecccfc0dcb6b5fc7d
