Fix ruby warnings

[swamp09]

This fixes following warnings.

/lib/dragonfly/server.rb:31: warning: `*' interpreted as argument prefix
/lib/dragonfly/server.rb:35: warning: `*' interpreted as argument prefix

/lib/dragonfly/url_mapper.rb:27: warning: character class has duplicated range: /[\w_]:[\w_]/
/lib/dragonfly/url_mapper.rb:46: warning: character class has duplicated range: /\:[\w_]+/
/lib/dragonfly/url_mapper.rb:54: warning: character class has duplicated range: /:[\w_]+/
/lib/dragonfly/url_mapper.rb:54: warning: character class has duplicated range: /.:[\w_]+/
/lib/dragonfly/url_mapper.rb:65: warning: character class has duplicated range: /([^\w_]):([\w_]+)/
/lib/dragonfly/url_mapper.rb:76: warning: character class has duplicated range: /[^\w_]:[\w_]+/

/lib/dragonfly/routed_endpoint.rb:27: warning: assigned but unused variable - e
/lib/dragonfly/routed_endpoint.rb:29: warning: assigned but unused variable - e

/lib/dragonfly/model/class_methods.rb:89: warning: assigned but unused variable - e

[markevans]

merged in - thanks