update travis-lint
update guard dependencies
update appraisal gem, generated gemfiles
update ruby-graphviz version, drops 1.9.2 support
update test to support default role_path

The role_path default was changed from /var/chef/roles to the user's
home directory, `~/.chef/roles` instead. Use matchers to allow for both.
remove buildheroes, update readme
update travis for ruby versions
use Rake's clean/clobber methods over FileUtils

It's much safer to specify the correct paths instead of rm_rf.
add RuboCop
replace tailor with rubocop
address rubocop style
add Guardfile for local development
CHANGELOG update