Switch to using opacity since this is how most software works.
Transparency is simply confusing to the average user.
Linux/Windows GUI to be updated in later commits.
The code was never working properly ( tested by @tadanokojin ) so let's
clean up and remove it. If someone actually wishes to maintain it then
they can re add it and update the code to a functional stage.
This pull request is for the pending reorganization of the folder structure on GSdx,
making it better organized and easier to work with.
Also remove unused GSTextureFX.cpp file.
JC