Issue #2815: setup CircleCI
Issue #2815: setup CircleCI

HubSpot/checkstyle,sharang108/checkstyle,izishared/checkstyle,MEZk/checkstyle,rnveach/checkstyle,ilanKeshet/checkstyle,baratali/checkstyle,sabaka/checkstyle,liscju/checkstyle,jonmbake/checkstyle,AkshitaKukreja30/checkstyle,izishared/checkstyle,liscju/checkstyle,MEZk/checkstyle,checkstyle/checkstyle,jochenvdv/checkstyle,ilanKeshet/checkstyle,liscju/checkstyle,sabaka/checkstyle,sirdis/checkstyle,romani/checkstyle,checkstyle/checkstyle,rnveach/checkstyle,sirdis/checkstyle,vboerchers/checkstyle,checkstyle/checkstyle,nikhilgupta23/checkstyle,rnveach/checkstyle,vboerchers/checkstyle,checkstyle/checkstyle,izishared/checkstyle,romani/checkstyle,rnveach/checkstyle,MEZk/checkstyle,checkstyle/checkstyle,sharang108/checkstyle,rnveach/checkstyle,baratali/checkstyle,ilanKeshet/checkstyle,bansalayush/checkstyle,nikhilgupta23/checkstyle,romani/checkstyle,vboerchers/checkstyle,baratali/checkstyle,HubSpot/checkstyle,jonmbake/checkstyle,bansalayush/checkstyle,nikhilgupta23/checkstyle,rnveach/checkstyle,bansalayush/checkstyle,AkshitaKukreja30/checkstyle,romani/checkstyle,jochenvdv/checkstyle,jochenvdv/checkstyle,sirdis/checkstyle,HubSpot/checkstyle,sharang108/checkstyle,jonmbake/checkstyle,checkstyle/checkstyle,romani/checkstyle,sabaka/checkstyle,AkshitaKukreja30/checkstyle,romani/checkstyle