Removed the JSCollectionsImplementor stuff. It had a few drawbacks:
 - Calling new Array() is actually allowed in JS, and is also useful
 - Separating the implementations of Array and Map from the interface is
not consistent with the way it works for Date
 - The way it was done introduced cyclic dependencies between the shared
and server modules in the shared module test scope.
Temporarily fixed build maven-plugin-it. All the pseudo projects it
tries to build have a reference number to the STJS project version
hardcoded. We should probably find a way to read that version number
from maven-plugin-it to prevent the build from failing when the
developer's .m2 repository is empty.