Change calibration circles to some easier to use prefab

[olykos]

No description provided.

[olykos]

It would be ideal to use prefabs that are distinct for each location (for example a 90 degree corner rotated appropriately for each). Here's why:

We are now saving state for the circles between runs. If someone swaps left to right we're not going to know because the sprites are the same. If then another person runs it, the circles will still be swapped due to saved state, and he will have no way of knowing.

EDIT: Actually this is not a huge deal since pressing r will fix any swaps, but still nice to do if it's not too hard.