Build: move BuildCommand.Run into a RunContext command to allow testing for cancellation, put cancellation in `Run`
Build: move BuildCommand.Run into a RunContext command to allow testing for cancellation, put cancellation in `Run`

timsutton/packer,hashicorp/packer,grubernaut/packer,bryson/packer,tas50/packer,timsutton/packer,tas50/packer,dave2/packer,pecigonzalo/packer,rnaveiras/packer,timsutton/packer,tas50/packer,timsutton/packer,paulmey/packer,timsutton/packer,ricardclau/packer,paulmey/packer,rnaveiras/packer,rnaveiras/packer,tas50/packer,mitchellh/packer,paulmey/packer,paulmey/packer,ricardclau/packer,dave2/packer,dave2/packer,bryson/packer,ricardclau/packer,rnaveiras/packer,pecigonzalo/packer,bryson/packer,pecigonzalo/packer,grubernaut/packer,rnaveiras/packer,bryson/packer,hashicorp/packer,ricardclau/packer,mitchellh/packer,hashicorp/packer,grubernaut/packer,tas50/packer,grubernaut/packer,ricardclau/packer,bryson/packer,dave2/packer,timsutton/packer,tas50/packer,paulmey/packer,dave2/packer,grubernaut/packer,mitchellh/packer,pecigonzalo/packer,mitchellh/packer,paulmey/packer,hashicorp/packer,rnaveiras/packer,ricardclau/packer,bryson/packer,grubernaut/packer,mitchellh/packer,dave2/packer