Merge pull request stleary#52 from johnjaylward/OptionalTypeConversion

updates Test cases to support new JSONML and XML conversion options

Merge pull request stleary#39 from johnjaylward/FixNegativeZero

Fix negative zero

Merge pull request stleary#30 from stleary/confirmValueToStringFix

Fix tabs, add valueToString() test to JSONObjectTest

works with JSON-java maven release 20141018

Add method comments so JavaDoc will pick them up.