breakpoint-slicer syntax support added.

I did some work on converting this to a syntax that supports a [breakpoint-slicer](https://github.com/lolmaus/breakpoint-slicer) style syntax. It is backwards compatible (no breaking changes).

~~I still need to write the tests for all of this, and will do so very soon. But you'll have to run them as they all fail on Windows as referenced in #2. (then again I suppose I could just reference Travis - don't want to take any chances though)~~

EDIT: tests added!

I figured I would just open the PR for now so you can have a little inspect of it. :)