Add "start" view of the simulation

[jonathanGB]

• canvas must have the x-axis
• hovering over the x-axis shows a circle that follows the mouse; on click, add a robot at this point
  • add a label
  • in a bubble, show x value, label, and state (radio); all modifiable
  • on right-click, default to faulty-robot?
• show list of previous setups to start from (stored in localStorage)
  • button to store setup, which prompts for a setup name before
• possibility to paste a custom setup into textarea
• "start generating" button, which starts generating in the background [next issue] and blocks further changes to the setup

[jonathanGB]

Current todo:

• Update position onchange of the x input (and vice-versa)
• Add a meter to change the distance visible v

[jonathanGB]

• Make 1st faulty robot the origin of the axis
  • Should we draw a faulty robot by default?

[jonathanGB]

• Fix the x input to work relative to the origin position now that it's moving

[jonathanGB]

The start view is pretty much complete at this point, so I am closing this issue.