ignore vendor paths for linting

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
temporarily remove guard from gemfile for travis testing

travis 1.8.7 testing cannot work with guard due to dependency on celluloid which requires ruby 1.9.2. it is still worth running the tests for 1.8.7 since some systems (eg ubuntu 12.04) carry old rubies by default and are supported by hardening

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>