refactor: simplify router arg parsing
refactor: simplify router arg parsing

using the same "always shift one" approach as in proxy_args

paladin74/weave,rade/weave,beni55/weave,paladin74/weave,n054/weave,aaam/weave,n054/weave,philipz/weave,awanke/weave,narry/weave,kidaa/weave,tomwilkie/weave,squaremo/weave,aaam/weave,achanda/weave,paulbellamy/weave,paladin74/weave,n054/weave,philipz/weave,narry/weave,rade/weave,philipz/weave,beni55/weave,awh/weave,awh/weave,squaremo/weave,paladin74/weave,n054/weave,dpw/weave,squaremo/weave,bboreham/weave,aaam/weave,narry/weave,weaveworks/weave,squaremo/weave,dpw/weave,beni55/weave,cgvarela/weave,cgvarela/weave,awh/weave,paulbellamy/weave,bboreham/weave,aaam/weave,awanke/weave,awh/weave,awanke/weave,tomwilkie/weave,achanda/weave,BWITS/weave,narry/weave,paladin74/weave,narry/weave,aaam/weave,kidaa/weave,tomwilkie/weave,paulbellamy/weave,kidaa/weave,tomwilkie/weave,rade/weave,rade/weave,beni55/weave,weaveworks/weave,kidaa/weave,dpw/weave,dpw/weave,bboreham/weave,rade/weave,BWITS/weave,beni55/weave,weaveworks/weave,bboreham/weave,BWITS/weave,dpw/weave,squaremo/weave,BWITS/weave,awanke/weave,cgvarela/weave,achanda/weave,tomwilkie/weave,bboreham/weave,kidaa/weave,n054/weave,cgvarela/weave,awanke/weave,cgvarela/weave,BWITS/weave,philipz/weave,achanda/weave,awh/weave,paulbellamy/weave,weaveworks/weave,philipz/weave,achanda/weave