Allow setting other service_* parameters #76
Description
Based on the text at the bottom of https://docs.coveralls.io/supported-ci-services, my understanding is to use Coveralls with an unsupported CI provider, you need to set the other service_* parameters in https://docs.coveralls.io/api-reference.
There doesn't currently appear to be a way to do this though which is preventing me from using this project.
This issue is related to #23.