Add Chisel to start-herb.sh

[mkoval]

@mklingen confirmed in #23 that Chisel currently runs in the background and needs modification, to add enable/disable service calls, before we should run it by default.

[mklingen]

It has a "TogglePause" service. The only change needed would be a ros param in the chisel server that tells it whether to start paused or not. The other option is to start pasued, never unpause, and instead write some kind of service call to generate a mesh instead.