Merge pull request #64 from DamirSvrtan/development

Provider Integration + RSpec3 update + Test on 3 Ruby versions
Updating version information.
Use private Client#ApiKey conversion function.
Remove Hash patching Util.
Make util assert code more readable.
Remove unused add_query_string function, transferred long time ago to the request class.
SimpleCov add filter not to look in spec folder.
Use attr_accessor instead of attr_reader + attr_writter on Response#headers.
Use Stormpath::NilError on empty errors.
HttpClientRequestExecutor indentation fix.
ApiKey new line fixes.
Remove Client#cache_stats.
Refactor password fetching in UsernamePasswordRequest.
Better username assignment on BasicAuthenticator initialization.
Refactored sauthc1_signer.rb
No need to set api_key on client initialization twice.