Add an attribute for LabWindows/CVI panels for setting transparency.
Currently, in order to achieve this behaviour users are forced to workaround this using Windows API.
Having an attribute for this purpose would allow users to benefit from this functionality more easily and would make LabWindows/CVI programs more cleaner.
Related forum discussion: http://forums.ni.com/t5/LabWindows-CVI/Transparent-Main-Panel/m-p/3172386
