Support a cross build to support Linux Embedded efforts.

This needs to be a staged effort with the following known issues to be supported at the end of the effort:
* allow for the specification of a cross platform to build for, either on the ant command line or via an ant task
* allow for the platform specification to be done via a properties file that is a well know location in the forest, or separate from the forest
* allow for a developer to build for both the host platform, as well as one or more cross platforms
* extend import support for cross build tools needed for ARM (and maybe ATOM?)
* handle partial build case so that the proper native shared are copied (if available and desired, ie webnode may not be supported on a paltform)
* cross build glass, runtime, media, webnode