Added JSStubOnly attribute for simplification creation of class sutbs.
Rewrited test for JSStubOnly attribute that makes it muh easy to understand.

--HG--
rename : Tests/SpecialTestCases/ClassMarkedAsStubOnly.cs => Tests/SpecialTestCases/ClassMarkedWithMetaAttibutes.cs
Merge pull request #324 from iskiselev/master

Added JSStubOnly attribute for simplification creation of class sutbs.