Cast CGI data to hash, as that's what the code really expects

Fixes an issue where users pass in the `ENV` hash-like object is passed in as the cgi_data to new Notices.
Speed up notice generation by avoiding copying data and putting most common cases on top
cleanup gemspec
Merge pull request #329 from grosser/grosser/gemspec

cleanup gemspec
Comment out @wip scenarios to facilitate running parts of the suite
Add 4 to version sniffing code
PR feedback
Merge pull request #335 from airbrake/fix/cucumber-suite

Comment out @wip scenarios to facilitate running parts of the suite
Merge pull request #327 from airbrake/feature/faster-params-cleaning

Speed up notice generation by avoiding copying data and putting most common cases on top
Clone to ensure we do not mess with the provided data
Merge pull request #337 from airbrake/fix/rails4-is-here

Add 4 to version sniffing code
Merge pull request #326 from airbrake/fix/cast-ENV-to-Hash

Cast CGI data to hash, as that's what the code really expects
fix having symbols in the environment blows up filter_parameters with blocks