mechanical: Rework after first prototype
mechanical: Rework after first prototype

* Add guides on end gaps
* Redesign of sensor box
* Add alignment object
* Resize RPi encloser
* Resize LCD display enclosure
* Add o-ring to bottom endcap

Signed-off-by: Mark Gray <06eec037e872338f9fc82f5e66f9b35f89980ff4@gmail.com>

mrmarkgray/haldane