Allow omitting namespaces for unambiguous functions/actions

-introduce a vocabulary element for services to declare one or more default namespaces, as per simplified url proposal ( https://www.oasis-open.org/apps/org/workgroup/odata/email/archives/201511/msg00007.html ) -4.01 services need to support invoking unqualified actions/functions defined within a default namespace -State that bound actions/functions SHOULD NOT conflict with any properties on the type they are bound to -Define a precedence for resolving possible conflicts as per simplified url proposal: -declared property=>function/action=>open property -Services must also allow qualified invocation -make sure that docs are clear that services must not require clients to understand custom annotations, but OData annotations may imply semantics that a client reporting support for that version of the specification would need to understand in order to work correctly with the service.

https://www.oasis-open.org/apps/org/workgroup/odata/download.php/59028/odata-v4.01-wd01-part1-protocol.docx https://www.oasis-open.org/apps/org/workgroup/odata/download.php/59029/odata-v4.01-wd01-part2-url-conventions.docx https://tools.oasis-open.org/version-control/browse/wsvn/odata/trunk/4.01%20spec/ABNF/odata-abnf-construction-rules.txt