Merge pull request #9 from rrch/master

Add unit tests.
Merge pull request #11 from rrch/master

Add tests for exported functions.
Merge pull request #12 from rrch/master

Remove unneeded ADD instruction.
Merge pull request #13 from rrch/master

Add missing environment variables to the request.
Merge pull request #14 from rrch/master

Add lint config and fix issues reported by lint.
Merge pull request #15 from rrch/master

Add code coverage reporting.
Merge pull request #16 from rrch/master

Bring test coverage up to 100%.
Merge pull request #17 from rrch/master

Rename CONTRIB.md to CONTRIBUTING.md.
Merge pull request #21 from rrch/master

Invoke the callback with an error if the request object passed to an api...
Merge pull request #22 from rrch/master

Add system.getBackgroundRequest api.