Adds handling for custom action commands to OctoPrint. Action commands are sent from the RepRap machine in the form //action:command.
The plugin allows OctoPrint to execute a system command or send G-code to the printer in response to an action command.
Install via the OctoPrint plugin manager.
As of the latest Marlin bugfix-1.1.x version, the command M118 can be used to echo output to serial, meaning that M118 //action:dostuff would cause this plugin to try to handle the dostuff command when //action:dostuff was echoed back on the serial console.
A future application of the plugin would be to add actions in the RepRap machine's firmware so that hosts could respond. For example, when Marlin is killed because something is wrong it would echo //action:poweroff and the attached OctoPrint instance could use this action command to trigger the printer's power outlet to switch off.
