Add code sniffer rules for 2.0 goals.
Do not require test classes to be namespaced.
Remove side-effects from test files.
Merge pull request #551 from bantu/2.0-code-sniffer

Code Sniffer rules witnessing PSR-4 and related goals

* bantu/2.0-code-sniffer:
  Remove side-effects from test files.
  Do not require test classes to be namespaced.
  Add code sniffer rules for 2.0 goals.