Add test for -[NSMutableString initWithCharacters:length:]
Merge branch 'master' of github.com:apportable/FoundationTests
Add -[NSMutableString initWithCharacters:length:] test to assert the resulting string
Add simple +[NSJSONSerialization JSONWithData:options:error:] success test
Merge branch 'master' of github.com:apportable/FoundationTests