Add hanna to development dependencies. Avoid multiple version stateme…

…ts for shotgun in gemspec (makes gemspec usable with bundler). Add min version to haml dependency corresponding to version specified in tilt's gemspec.

That way it is possible to run on a clean system like this:

    echo 'gemspec' > Gemfile
    bundle install
    bundle exec rake test # or something else

This is especially important for running a CI server or generating the docs (running hanna with a recent rdoc gem installed results in an exception).

sinatra.gemspec

@@ -102,9 +102,9 @@ Gem::Specification.new do |s|
   s.extra_rdoc_files = %w[README.rdoc README.de.rdoc README.jp.rdoc README.fr.rdoc README.es.rdoc LICENSE]
   s.add_dependency 'rack', '>= 1.0'
   s.add_dependency 'tilt', '~> 1.1'
-  s.add_development_dependency 'shotgun', '>= 0.6',   '< 1.0'
+  s.add_development_dependency 'shotgun', '~> 0.6'
   s.add_development_dependency 'rack-test', '>= 0.3.0'
-  s.add_development_dependency 'haml'
+  s.add_development_dependency 'haml', '>= 2.2.11'
   s.add_development_dependency 'builder'
   s.add_development_dependency 'erubis'
   s.add_development_dependency 'less'
@@ -114,6 +114,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'radius'
   s.add_development_dependency 'markaby'
   s.add_development_dependency 'coffee-script'
+  s.add_development_dependency 'hanna'
 
   s.has_rdoc = true
   s.homepage = "http://sinatra.rubyforge.org"