Startup refactor and general cleanup

This is step one on refactoring the startup to be configured.

Mainly it is a first parse at simplifying the config file reading.
It relies on the latest version of the emacs module (https://github.com/ensime/ensime-emacs/pull/22) as that PR declares the ensime file location as well as the cache dir location (and they are now required).

Moved some test util methods around and cleaned up so unused methods.