Adding a few progeny options

@eleith PTAL

added the following options: 

1. `supportsGlob`, which utilizes the `glob` directory to expand glob syntax in `import/require` statements where supported by the compiler. This currently only affects stylus, since its the only one to support glob syntax.
2. `handleDirectory`, which gets called when as a supplement to the normal file expansion to take into account languages that support directory level imports, specifically in stylus (`@import fooFolder/` will attempt to import `fooFolder/index.styl` if it exists)
3. `shallow`, which subverts the original recursive searching behavior of progeny and only returns the direct parents of the file / data in question.

added tests for the above options. might attempt to break these apart to get them upstream if possible, when i get a chance.