This change addresses the Code Review from the previous commit. Changes include the following

 Stronger Validation for Openstack.config.
 Better handling of detecting and raising NullReferenceExceptions
 Removal of dead code in a few places
 Added ability for each ServiceProvider to supply a ServiceMap which translates his name for a CoreService to something we can work with.
 Optimized code for dealing with Runspaces.

This change implements 2 separate use cases for Multi-Vendor support.

a. Initial Bootstrapping
b. Switch Providers

Change-Id: Ided462e5050214321e1ead50cf0498707d59128f
Partially-implements: blueprint implement-multiple-vendor-support