adding tests for setting zone
adding tests for diff and from
adding tests for unix timestamp and unix millisecond offset
zone tests for cloning, start/endof, resetting offset with local and utc
zones outputting correct timestamped date with toDate
adding zone tests for isSame, isBefore, and isAfter
adding some tests for zones outside the -12 to +12 range
adding tests for adding/subtracting over dst
fixing travis
undoing grunt task test files
adding tests for parsing strings for timezone info
adding tests for shorthand zone setters via -15 to +15
merging develop into feature/zone-setter
fixing zone getter and setter test
adding isDST teste
Merge pull request #671 from timrwood/feature/zone-setter

Making moment#zone a setter