Make WordCrams from shapes, from image masks

Let's get this ball rolling!

@simpsus - sorry for taking so long on this. Thanks for being patient, and thanks for pushing WordCram along! :smile_cat: 

I made a rel-060 branch, since I think getting shape-based crams is worth a new minor version number. (At least!) This PR is into that branch. There's other stuff to sort out, and once it's all ready, we'll get WordCram 0.6.0 out the door.

* I re-wrote ImageShaper with one fast method for making shapes from masks. It only works with Processing's PImage and color datatypes, which I think is fine, because WordCram is so dependent on Processing. You can't make a WordCram without a Processing sketch/PApplet, so you can always get a PImage and a color integer.
* I deleted the ShapeBasedPlacer methods that created Shapes from Images and Words - those responsibilities belong with WordShaper and ImageShaper, respectively. I had to make the WordShaper API more friendly for this, which is a bonus.
* I'm not in love with `drawAllVerbose()`, but I think I can live with it for now. (I'd like to maybe use Observers, but that can come later.) Also, there are some bugs in there, with reporting progress.