Fix an assert in mini_emit_stobj () when sgen+gsharedvt are used together.
[WCF]: Add configuration support to ServiceContractGenerator.

* Implement ServiceContractGenerator.GenerateBinding() and
  GenerateServiceEndpoint().

* Fix Namespace logic in ServiceContractGenerator.

* MetadataTests/ImportTests.cs: Add BasicHttp_Config() and
  BasicHttp_Config2().

Fix commit message of eb285f121c67eaf134a01e29e9cf9bef084c2fad.
Oops, base on ecff71a which fixed the commit message.