Fixed the list branches method

Also added in the option to pass in repository-name so you can fetch branches from various repositories
Clean up the config settings to make more sense
Send git logging to /dev/null in tests leave as option
Changed the checkout_git_branch command to be checkout_branch
Move the create_git_branch command to create_branch
Change options to be class variable instead of instance variable
Silence git for tests and add github test
Add test to verify pull request response is correct
Merge pull request #5 from wallerjake/add_tests_for_github_class

Added test cases for github