Revert "explicitly install libpython, not python on travis"
Revert "explicitly install libpython, not python on travis"

This reverts commit 33fdde8b2fc861cb65ed48a54bc79214dc7ae597.

[skip appveyor]

neilstephens/opendatacon,neilstephens/opendatacon,neilstephens/opendatacon,neilstephens/opendatacon,neilstephens/opendatacon,neilstephens/opendatacon,neilstephens/opendatacon