Unicode problematic

[longouyang]

Copying code from PDFs (e.g., in class solutions) often doesn't work because it introduces (potentially invisible) Unicode characters like '\xe2'.

This might be a feature - we could add a custom error message like "don't just copy/paste the homework solutions".

The broader point: this is something we should handle, one way or another.

[juliusc]

On the WebChurch side, we could transform the names as per the way it's already done, so you could give arbitrarily weird names. From a UI standpoint, maybe a solution is to have a JS regex that scrubs all unicode characters so they never show up? (this would solve the invisible char issue)