Rename Guard::Dsl to Guard::DSL
Refactor and document Guard#guards, Guard#groups, Guard#add_guard and Guard#add_group
Move Guardfile evaluation stuff into Guard::Guardfile::Evaluator
Deprecate Guard::Guardfile in favor of Guard::Guardfile::Generator
Rename Guard::DslDescriber to Guard::DSLDescriber and refactor it
Re-add Guard's deprecated methods (now in Guard::PluginUtil)
Allow Guard::PluginUtil#initialize to take 'guard-xxx' or 'xxx' as argument
Move colors from Guard::UI to Guard::UI::Colors
Improve coding style