Revert "Build with native arch on travis"
Revert "Build with native arch on travis"

This reverts commit 0361783c1b5e0361c4f6dbad45bb9be4a862028e.

ukoeln-vis/ctpperf,szellmann/visionaray,tu500/visionaray,szellmann/visionaray,tu500/visionaray,ukoeln-vis/ctpperf