pdParamString: fix error with character escaping if a blank param string is passed
Fragment effect: default to "fast" processing mode

Also, reduce max fragment count to 25.  I can easily change it back, but
the image quickly becomes so blurry that I'm not sure extra fragments
are worth the performance loss....?
Save/Save As: make sure a non-blank filename is passed to the common dialog API

Otherwise, it will fail.  (This is news to me!)
Fix extra space appearing in auto-incremented filenames
Effects -> Test; do not apply an effect by default

I include this menu item in the IDE only so other coders can more easily
play with their own PD effects; however, because it does not trigger
Undo/Redo creation, you're screwed if you click it randomly.  This
should prevent that.
Processor: remove unnecessary debug messages
Menu icons: placeholders for various new menu items

PD's whole mechanism for storing and loading menu icons will be changing
in the near future, but in the meantime, I'd like to start soliciting
feedback on things like Layers and the new Undo/Redo engine.  To that
end, I thought it would be worthwhile to plug in some default icons for
various new menus (like everything in the Layer menu).