liq| er| ui|: display "ElvishRender" as "Elvish Render"
liq| er| shader|: + mia_pyhsicalsky, mia_physicalsun. (Not Complete, cause the shaders are NOT right)
liq| er| shader|: +er_physicalsky( with liquidShaderNodes_initParams_pl() )
1. after creating er_physicalsky node, I assign physicalsky.dll to the shader node, and update the parameters UI
2. add shader parameters into Visitor::visit_er_physicalsky()
3. camera shader can not be liquidShader or liquidSurface

TODO:
the input plugs in er_physical shader node can't be accessed, cause the plugs are not add into $shaderNode.rmanShader instead of $shaderNode itself. So, convertShadingNetworkToRSL() can't access the parameters.
So, I have to add these parameters to er_physicalsky shader node as plugs.