Replace SELECT and INSERT queries into a single INSERT SELECT query when generating the closure table for a new entity.
Put $ inside {}.
Use $rawTable instead of $t in the raw query that inserts new nodes into closure_table.
Removed DB::transaction call now that there's only one query within ClosureTable::insertNode.
Merge pull request #95 from tomzx/fixes/92-optimize-entities_closure-generation

PR for #92