Mode 1908 Completed support for having CompositeBinaryStores in EAP

This pull request contains the commits https://github.com/ModeShape/modeshape/pull/799  but in slightly "changed" form, in that a part of those commits have been squashed and one commit removed altogether. 

The EAP integration part of the original pull request has been completely rewritten (and unfortunately is one of the most complex pieces of AS7 integration to date).

In the process of rewriting this integration, a number of other EAP related bugs were spotted (like removal of services during _RemoveStepHandlers_ or _relative-to_ path resolutions).