Issues with Excel Import

- Made changes to TeiidDdlImporter to handle the extension properties.  The AstNodes for extension properties will be namespaced with the teiid namespace URI, (if it is available - with addition of Option Namespace statement).  That is the primary way we should resolve against our Designer MEDS - check for NS URI match to the registered MEDS.  The changes also handle the standard NS prefixes - (as fallback) until the teiid NS statements make it into the DDL.
- TeiidImportManager resolves Array OOB exception encountered
- MxdConvertor - changed the URI template for generated MEDS to match the expected teiid URIs.  There is also a HACK to fix error resulting from TEIID-2974 until teiid gets their fix in.