discussion: Consider preventing trades that may be considered dust.

[JoeGruffins]

For coins who's clients check for dust outputs, consider preventing trades with server that would definitely fail due to values being too low.

[buck54321]

This issue has actually increased in importance now that we have implemented the new trade limit system, in which low-fee pair markets can have ultra-small lot sizes. Lot size and market conditions definitely can align to make dust outputs. Solution needed.