Fixes #151: Better error messages for incorrect use of options
Fixes #151: Better error messages for incorrect use of options

1yvT0s/os,gpndata/os,fentas/os,duguhaotian/os,rowhit/os,1yvT0s/os,juliengk/os,arnononline/os,imikushin/os,rancherio/os,arnononline/os,datawolf/os,gpndata/os,rancher/os,gpndata/os,luxas/os,imikushin/os,gizmotronic/os,ibuildthecloud/os,maxfierke/rancher-os,duguhaotian/os,rowhit/os,rancher/os,SvenDowideit/os,juliengk/os,OnePaaS/os,hairyhenderson/rancheros,rowhit/os,1yvT0s/os,ibuildthecloud/os,maxfierke/rancher-os,rancherio/os,hairyhenderson/rancheros,luxas/os,gizmotronic/os,duguhaotian/os,OnePaaS/os,fentas/os,OnePaaS/os,datawolf/os,hairyhenderson/rancheros,SvenDowideit/os,fentas/os,luxas/os,datawolf/os,arnononline/os,maxfierke/rancher-os,rancherio/os