Update original Design Paper

[EtiennePerot]

Thanks for resurrecting this document. However, little of it still applies to parcimonie.sh in its current form. Can you make it clear that this is for the original parcimonie implementation? Please do the following:

• Renaming the file to parcimonie-original-design.md.
• Updating the link in README.md.
• Adding an italicized disclaimer at the top explaining that this document is about the original implementation of parcimonie, not the Bash reimplementation parcimonie.sh, and that the document is preserved here because it is no longer online elsewhere.

Thanks!

[BoBeR182]

You should be good to go.