Merge pull request #24 from Cerberus98/mergeup

Continues updating tests with new db_api calls
Added optimized driver tests
Added optimized port delete tests
Added network delete in optimized driver test
Fixed flake8
Merge pull request #26 from jkoelker/first_draft_optimized_tests

First draft optimized tests
Subnet and Network plugin tests

Adds test coverage for the subnet and networks calls.