Add the dnsimple module

This is a module for interacting with the DNSimple API (http://developer.dnsimple.com/) based on the dnsimple-python library by Mike MacCana (https://github.com/mikemaccana/dnsimple-python).

It supports the following options:
- Domain retrieval, creation and deletion
- Record retrieval, creation, deletion, and updating
- Mutually exclusive records (eg only one A record for test.foo.com) using the ``solo`` key.
- Supports check mode