Test against Ruby 2.1 / 2.2 on Travis CI
Merge pull request #159 from tricknotes/ruby-2.2

Test against Ruby 2.1 / 2.2 on Travis CI
Test more json values
Require json
Merge pull request #165 from sstephenson/test-json-values

Test more json values
Merge branch 'master' into duktape
Encode first
Return strings are now utf-8