added rspec support

[elreplicante]

Added support for testing with rspec

[evanleck]

I'm torn about merging this because it means we can't use Sinatra::Namespace but the benefit of testing is clear (and obvious). I'm woefully uneducated about the specifics of rspec but how does it pick up the Sinatra application just from requiring "app/routes/root.rb"? Is that treated as the global Sinatra::Application?

Do you think it'd be worth it to convert this project to a modular style app instead of a classic style app? Do you think that would solve this problem?