ethereum/go-ethereum — pull request #203 by fjl (2014-12-09 10:22:35+00:00)
Title: RLP: remove signed integer support and fix a panic

There is no canonical encoding for signed integers. They don't mix well with the 'no leading zeros` rule.
Given that RLP is part of consensus I think it's better to leave them unsupported and
define an encoding later, when some protocol requires negative numbers (could be never).

An alternative solution would be to return an error for negative values.