TEIID-2678: Various ODATA Issues

1) The metadata building correctly constructed now from runtime metadata. Moved the EDM metadata builder from teiid-odata project into odata-translator project.
2) in the metadata captured the original entity type, so that responses can be parsed correctly from feed.
3) Added name space qualifier for OData specific metadata proeprties
4) Apache CXF was returning headers in ArrayList, previously with original http transport it was returning String, fixed
5) Added new "ComplexType" and "ColumnGroup" metadata properties to represent the embedded tables, instead of complex use "EntityType" leading to confusion. This streamlined logic dealing with 1-1 matches where content is embedded in the parent table
6) Key column matching code was using positional matches, rather than keys on whole. Fixed.
7) Added returning 404 as no content available on odata request. Previously to accommodate for this the code was swallowing any other errors
8) SAP Netweaver Gateway does not work CAPITAL logical operators (AND,OR) fixed to always be lower case. Same with NULL. This is not part of odata spec, just idiosyncrasy with SAP Gateway
9) Added unit tests for most of the above