travis: remove autotools build in favor of meson
travis: remove autotools build in favor of meson

related to https://github.com/i3/i3/issues/4086

Airblader/i3-original,i3/i3,Airblader/i3,Airblader/i3,Airblader/i3-original,stapelberg/i3,stapelberg/i3,Airblader/i3-original,Airblader/i3,i3/i3,i3/i3,stapelberg/i3,Airblader/i3,i3/i3,Airblader/i3-original,Airblader/i3-original,stapelberg/i3