drawAlertWindow customization

[lalalandsynth]

Customizing an overwrite preset alert window.

1. I would want to be able control the size of the window, way too large for our use.
2. When using a beveled outline the alert window background is always drawn in a solid black color, setting it to transparent would help in this case. (see black corners in this example.
3. Being able to set the background to transparent would allow for a fill rect inside to "fake" the size of the window.