Removed duplication from registering commands
Removed duplication from registering commands

This also drops feature: attach to nunit-agent.exe, and if not found to nunit.exe

fbdegroot/AttachTo,ziyasal/AttachTo,madskristensen/AttachTo,nmklotas/AttachTo,alexdresko/AttachTo,Tasteful/AttachTo,whut/AttachTo