Tweaking Octorpint user interface for CNC

[JensDyvik]

I have started work on tweaking the Octoprint interface for easy to learn operation of CNC milling machines.

I managed to remove two unnecessary tabs and order the tabs to display gcode preview first:

To make changes i edited the config.yaml file:

By following these steps:

1. SSH into the pi with: "ssh pi@octopi.local" and type your password
2. type "cd ~/.octoprint" to go the folder where the file is stored
3. type "nano config.yaml" to open the file in a text editor
4. type the changes
5. press "ctrl+o" and then "enter" to save your changes
6. press "ctrl+x" to exit
7. restart octoprint from the octoprint menu

The config.yaml file is well documented here: http://docs.octoprint.org/en/master/configuration/config_yaml.html

In order to get a preview in the gcodeviewer i had to untick the "Hide empty layers" option. It seems that if we have E steps after the X,Y, Z coordinates we can get a preview with balcak lines, not green jog lines. But that requires us to have one plugin extension to add the e-steps once the g-code is uploaded and another one to remove the e-steps once the g-code is started. Alternatively we can modify the gcodeviewr itself in the octoprint sourcecode. But having a green line showing the movements is anyway a great start,

I have also tested the https://plugins.octoprint.org/plugins/touchui/ It looks promising, but needs tweaking for cnc milling as well. Unfortunately the removal of unnecessary tabs in the config.yaml file breaks the touchui interface. So we will have to dig into the sourcecode of the touchui plugin