Pass `Vows.suites` instead of `Vows.batches` to Runner

`Vows.suites` is a `dict`.  It maps test filenames with a set of `Vows.batch` classes.

This allows the Runner more flexibility in how it divvies up tasks (grouped by filename, or by batches).
cli: Minor readability tweak
runner.abc: docstring for `is_excluded()`
Continuing to refactor runner… (This is an awful commit!  many assorted changes. sorry!)
Tweaked `Makefile` and `setup.py`