Added rspec (2.13 is the current), asserted in the README that we are us...

...ing Ruby 2, and added tests for ya_bish and help plugins (had to move them into their own folders to make that not dumb)

note: the change in help.rb was to fix a bug (choking on "help plugin_name" when there was a plugin_hash but extra was nil), and it should probably still work fine on ruby 1.9whatever, but I'm okay with saying "officially" steggybot is for ruby 2