Pulls db access out for better testing

Adds a new DB API layer can easily be mocked out for No DB testing of
the components of Quark. Also refactors the IPAM tests to utilize the
new API.
Merge pull request #14 from Cerberus98/pull_out_merge_in

Pulls db access out for better testing
Only run cover on quark

* Output html reports to .cover-report
Merge pull request #15 from jkoelker/quark_cover

Only run cover on quark
Added appropriate HTTP exceptions for create_ip_address