1st version of getDomainNames() POC

Straigt forward call to the getDomainNames method on the TransIP
API. No abstraction yet.
Setup abstraction for services

And implment get_domain_names for DomainNames service.
Change .gitignore
Cleanup comments
Use pylint to keep code format in check
Finish DomainService.getDomainNames()
Don't ship (encrypted) key with repo
Update README to reflect usage
Merge pull request #1 from mhogerheijde/feature/domain_names

Implement DomainService.getDomainNames()