Support function name decoration in dynamic loading

[gongminmin]

Some OpenGL/OpenGLES implements exports their functions with name decorations. A conversion is required before loading them. A document about decoration format:  http://msdn.microsoft.com/en-us/library/x7kb4e2f(v=vs.110).aspx

[gongminmin]

Done in changeset efb1462797f57997ef5d73dd58339cf754b4affb.