v4.0.4    Fixed problem of using it in Maya 2010.
v4.0.3    Tiny bugs fixed.
v4.0.2    Tiny bugs fixed.
v4.0.1    Renamed a variable to avoid potential conflicts. 
v4.0       Now compatible with Maya 2011.
v3.4       Fixed a small bug that only causes problem in 64bit Maya.
v3.3       Fixed a bug that deselects needed nodes when user
             checks checkBoxes not suppsed to be checked.
v3.2       Fixed a bug that fails to recognise '\' as path separator
             under OS other than Windows.
             Extra functions now supports mentalray.
v3.1      Adds support (only basic functions) for Maya psdFileTex
            node type and mentalray mentalRayTexture node type.