fix nvram test to not rely on line order

order of k/v pairs in nvram file is not important
more fixes to nvram test
Merge pull request #30 from pkit/tests_fixes

fix nvram test to not rely on line order
added tox py27 environment

added tox config for running unit tests
pep8 formatting fixes for mock
Merge pull request #31 from pkit/tests_fixes

added tox py27 environment