rename gcf -> cf everywhere
Merge pull request #111 from drnic/cli-rename

rename gcf -> cf everywhere
Update dependencies to allow 'cf' rather than 'gcf'

 - Move to latest version of cf-test-helpers and gomega
 - Make cf.go work with new cf-test-helpers
 - Update README.md since symlinking 'cf' as 'gcf' is no longer neccesary (yay)