Use new travis container infrastructure
Use new travis container infrastructure

Following instructions at http://blog.travis-ci.com/2014-12-17-faster-builds-with-container-based-infrastructure/

Tiross/atoum,CedCannes/atoum,gpaton/atoum,agallou/atoum,GuillaumeDievart/atoum,Tiross/atoum,mikaelrandy/atoum,jubianchi/atoum,CedCannes/atoum,mageekguy/atoum,vonglasow/atoum,mageekguy/atoum,mikaelrandy/atoum,tejerka/atoum,vonglasow/atoum,GuillaumeDievart/atoum,agallou/atoum,tejerka/atoum,gpaton/atoum,jubianchi/atoum