Gemspec contains non-US-ASCII characters, can't install on older rubygems

[jeremyevans]

This breaks installation on heroku's bamboo-1.9.2 stack, which uses ruby 1.9.2/rubygems 1.3.7. Because sinatra requires rack-protection, using the current version of sinatra on heroku bamboo 1.9.2 requires manually specifying an rack-protection 1.2.0 as a dependency before the sinatra dependency.