Travis tests: ensure latest bcbio installed
Travis tests: ensure latest bcbio installed

- Makes sure we get bcbio with py.test dependencies
- mount and change into bcbio code directory before running
  in-docker tests

chapmanb/bcbio-nextgen,a113n/bcbio-nextgen,brainstorm/bcbio-nextgen,biocyberman/bcbio-nextgen,chapmanb/bcbio-nextgen,vladsaveliev/bcbio-nextgen,vladsaveliev/bcbio-nextgen,biocyberman/bcbio-nextgen,a113n/bcbio-nextgen,brainstorm/bcbio-nextgen,brainstorm/bcbio-nextgen,chapmanb/bcbio-nextgen,a113n/bcbio-nextgen,biocyberman/bcbio-nextgen,lbeltrame/bcbio-nextgen,lbeltrame/bcbio-nextgen,lbeltrame/bcbio-nextgen,vladsaveliev/bcbio-nextgen