Support customizing jsmode for generic type parameters

[GoogleCodeExporter]

//Get metadata for T via JsObject / support specifying JsTypeAttribute for T
class MyList<T> where T: JsObject
{
  void foo() { return new T(); }   // return {} / return [] / return new ??
}

Original issue reported on code.google.com by DanelK...@gmail.com on 2 Jun 2014 at 9:11

[GoogleCodeExporter]

I think the last case, "return new ??" is already working when 
IgnoreGenericTypeArguments=false.

Original comment by Hultqvis...@gmail.com on 3 Jun 2014 at 6:29

[GoogleCodeExporter]

:-)

Original comment by DanelK...@gmail.com on 4 Jun 2014 at 9:58