Don't fill path with color / Ability to use painter instead of just custom particle path #91

Problem:

• when using a custom particle path this path gets filled, no matter if it's an arc, just a line,

Reproduction:

• use a custom path like an arc, bezier.
  -> the shape will be filled with one of the random colors

Solution:

• along using custom path, allow using painters too, so the particles are more customizable