Feature/refactor

Added docs and renamed variables for clarity. Modules now make use of RenderResult. Changes to the player allow for multiple renderers and export options. The config file now requires a list of Renderers and a list of exporters rather than just a list of handlers.
I don't think these names are necessary. As @kmjungersen pointed out, they aren't used, and it isn't really useful for either the module developer or the user.