Fix travis linux builds not running and other small travis tweaks.
Fix travis linux builds not running and other small travis tweaks.

appleseedhq/appleseed,pjessesco/appleseed,luisbarrancos/appleseed,luisbarrancos/appleseed,pjessesco/appleseed,pjessesco/appleseed,dictoon/appleseed,est77/appleseed,luisbarrancos/appleseed,luisbarrancos/appleseed,dictoon/appleseed,est77/appleseed,Vertexwahn/appleseed,luisbarrancos/appleseed,appleseedhq/appleseed,est77/appleseed,est77/appleseed,appleseedhq/appleseed,Vertexwahn/appleseed,Vertexwahn/appleseed,dictoon/appleseed,Vertexwahn/appleseed,pjessesco/appleseed,appleseedhq/appleseed,dictoon/appleseed,appleseedhq/appleseed,pjessesco/appleseed,Vertexwahn/appleseed,est77/appleseed,dictoon/appleseed