Uprev Collections and FRB

This addresses a bug in Collections impacts FRB and all MontageJS
applications on Chrome 30.  Chrome 30 introduces ES6 Array methods,
`keys`, `values`, and `entries`, which breaks an invariant that map
collection constructors depended upon: that these methods would only
exist on map-alike collections excluding Array.  Collections now depends
on an `isMap` property on all map-alike collections except Array to
distinguish a map from an array of entries.