[Performance] improve throughput of get of a cached CP

see: http://jsperf.com/slow-get-fast-get
[Performance] improve META lookup 10x throughput on chrome 32/34

This seems to not be a hit either way on safari/firefox/opera

see: https://gist.github.com/stefanpenner/ede92fbd00bf49bc5f09
see: http://jsperf.com/lookup-key-length/2