Geometry: New sample (#151)

* set up UI and code

* finish polyline calculation

* fix polygon rendering bug

* make unit switching UI, change location

* set up envelope

* enable unit switching

* lock pawn movement when pressing shift

* add press release to input system

* fix envelop bug, update envelope on tick

* make UI stay clicked

* fix envelope point render below terrain

* add to sample viewer, fix notification UI

* fix sample viewer envelop issue, code cleanup, fix SR

* address comment, update UI images

* unit switching on hover color changes

* unit switching UI complete

* finish UI feedback, fix crash, sort variables

* fix triangle bug, change input manager, fix UI

* fix color

Author: Jade-JadeH