Deleted AsyncConsumer, as ActiveSupport::Notifications#subscribe does not block IO
Added new entries to README
Added hook option and __all__ flag.
Changed minitest testing framework to RSpec, moved dummy rails app into tests as well as generator tests
Deleted duplicated files
Modified specs.watchr
Created spec/support/fake_controllers to group all fake controllers that
impressionist uses while testing.

Moved Dummy object into spec/support/dummy.rb file

Created a FakeActionController that responds to some methods, in order
to not load rails to test these, as it is time consuming doing this.

Users can now chose what filter, action, controller hook they want their
impressions to be saved.