#111 Allow different sounds for brushes

[Pere Pujal i Carabantes]

For example for the magic stars replacement.

This can be done allowing a field in the brush.dat file were one can specify the sound to play.

[Ruben Barkow-Kuder]

How do you define other sounds? or even turn sounds of the brushes off? (I don't like the default sounds)

at the moment there seem to be only four different sounds installed depending on the brush size.

maybe you should add nice default sounds to all brushes. for example here are some free brush sounds: https://freesound.org/search/?q=brush