Corrected specular export, support Phong

Made a correction to the way the specular coefficient is exported; this was using the 3DSMax **Glossiness** attribute. It has been corrected to use the 3DSMax material **Specular Level**. The **Glossiness** has been correctly remapped to the **Shininess** three.js attribute. 

Additionally included Phong shading, so the three.js Phong material will be used if Phong when used in 3DSMax - without this the bump maps are disregarded as they aren't rendered with Lambert materials (default material when unspecified). Blinn/Metal ShaderType materials will continue to be exported as Lambert.