Merge branch 'develop'
Finalized
Whoops forgot to bump version /cc @jonalmeida
Merge branch 'develop'

Conflicts:
	CHANGELOG.md
	build.gradle
Merge branch 'develop'
Merge pull request #67 from snowplow/develop

Version 0.5.0 with Version class fix
Changed release date
Fix for incorrectly escaped string (#69)

- Further inspection shows that the root cause is because we were still
  using toString when retrieving values our Payload.
- We know now that there will always be String values in the Payload set
  by TrackerPayload and SchemaPayload so we can remove the toString.
- This fix also lets us remove the ugly hack of stripping the end
  quotes from a value (!)
- Includes fixed test cases to no longer send non-stringified data
- Fixes #69
Fix double values to strings (#68)

- As part of the Payload interface, we allow values to be Objects to be
  added into the Payload. This allowed non-string values in.
- The 'Object' for values were intended for complex maps, but it no
  longer makes sense to send this data as anything except a string.
Updated Test