Core Service and Plugins Refactor

[bcpeinhardt]

Right now SchnauzerUI is one big project. There's a library and a CLI. There's a REPL driven development experience, which manages files and whatnot, and report generation with premade templates. I'd like to separate out a core service (the interpreter), and create a well defined plugin interface that the rest of the functionality uses.
This is probably more complicated than it sounds, because SchnauzerUI code doesn't make sense outside the context of a running webdriver. There's a non-trivial amount of "infrastructure" code that I'll need to find a home for.

[bcpeinhardt]

As a note on this ticket, there is a related ticket proposing a SchnauzerUI server, much like the selenium standalone server, which would allow straightforward creation of SchnauzerUI bindings in multiple languages.