next steps before release

[isplitt]

For now

• build simple model of whole printer (debug_rostock)
• add more pictures
• further optimize the code
  • carriage_for_traxxas
• document hal-sensor-board
  • schematics
  • BOM
  • pictures
  • update idlers_end.scad
• motor_end: add even more space above the motor for better cooling
• update doc

After that:

• include cooling into platform