README: add development instructions
Add .drone.yml
Remove .travis.yml
Merge pull request #17 from Clever/drone

Add Drone
Add comment to TooManyRequestsErrorTest

Comment explaining the mock http function.
Merge branch 'master' into support_rate_limiting_py

Conflicts:
	.travis.yml
Add test/requirements.txt to drone.yml script

That is: pip install -r test/requirements.txt