Start a new currency from an existing one

Give the ability to start a new currency based on a existing one.

Such a feature is required in case of a severe compromission of the currency either by cryptography obsolescence or protocol weaknesses.

Well ... let's start by making a currency. This question is out of topic

reopened

Seems interesting now since we're planning a 2.0 protocol change hardfork. It could be interesting to fork the current currency to make pre-release tests (after testing on GTest)