add test case for duplicate keys
allow duplicate keys in objects
convert source to string

http://es5.github.io/#x15.12.2
break single line comments on \r
fix travis-ci node versions
fix indent size
Merge pull request #59 from jordanbtucker/allow-duplicate-keys

Allow duplicate keys
add test case for duplicate keys
allow duplicate keys in objects
fix indent size
Merge pull request #63 from jordanbtucker/housekeeping

Convert source to String in parse
Merge branch 'develop' of https://github.com/aseemk/json5 into develop