Fix some stupid

Signed-off-by: Gregor Best <gbe@unobtanium.de>
Clean up prompt a bit, only show rtable on OpenBSD

Signed-off-by: Gregor Best <gbe@unobtanium.de>
Tmux: only set renumber-windows on OpenBSD

Signed-off-by: Gregor Best <gbe@unobtanium.de>
Use redshift-gtk instead of redshift

Signed-off-by: Gregor Best <gbe@unobtanium.de>