Only lint changed files compared to origin/master
Only lint changed files compared to origin/master

Instead of checking all files, drops the lint time down to a few
seconds tops

CartoDB/cartodb,CartoDB/cartodb,splashblot/dronedb,splashblot/dronedb,CartoDB/cartodb,CartoDB/cartodb,splashblot/dronedb,CartoDB/cartodb,splashblot/dronedb,splashblot/dronedb