PR for Release 0.6.0

Goals for this release:

- [x] Place words into arbitrary shapes, via image masks. _Done: https://github.com/danbernier/WordCram/pull/32._
- [x] Write to SVG files, instead of just outputting to the Processing sketch. _Done: https://github.com/danbernier/WordCram/pull/23_.
- [x] Put in some kind of observer interface, so you can get progress feedback as your sketch runs. See particularly https://github.com/danbernier/WordCram/pull/32#issuecomment-20315871. _Done on https://github.com/danbernier/WordCram/pull/40_
- [x] Fix for Right-to-Left languages. See #37.
- [x] Fix for minShapeSize being set to 0. See #42.

Stuff I decided not to fix for this release:

- A fix for [Issue #30](https://github.com/danbernier/WordCram/issues/30), "How to include Stop words?"
- When re-rendering a WordCram, don't reload web URL downloads - cache them on the file system. See https://github.com/danbernier/WordCram/issues/17.