Move forme/sinatra to forme/erb, since it is ERB and not Sinatra specific

Still keep the forme/sinatra file for backwards compatibility.
Allow running specs without rails or sinatra installed

Just warn if they aren't install, continue running other specs.
Add roda plugin

This just makes it slightly easier for roda users, but it is good
to get the same specs on roda and sinatra.
Use roda instead of sinatra on demo site
Bump vesion to 1.0.0