added rebuild_extensions to travis setup
added rebuild_extensions to travis setup

AntonioJBT/CGATPipeline_core,CGATOxford/CGATPipelines,AntonioJBT/CGATPipeline_core,CGATOxford/CGATPipelines,CGATOxford/CGATPipelines,CGATOxford/CGATPipelines,CGATOxford/CGATPipelines,AntonioJBT/CGATPipeline_core,AntonioJBT/CGATPipeline_core