AMF - improved writer
Supports Vector<T> writes as VectorObject, better support for IList
Supports writing with reflection
Added reflection MemberInfo cache in Amf3ClassDef
Can write doubles as ints or zeros as null
Merge branch 'master' into ps-amf
Added Amf3Utils.cs with some json<>amf conversion functions
Amf3Utils - misc cleanup
Merge pull request #307 from playscript/ps-amf

AMF writer improvements, json->AMF converter