Payment request URI syntax changed, from request=... to r=...

BIP 72 was changed to save six bytes in bitcoin: URIs.
Change release-process.md to sign release tags
Merge pull request #3362 from Michagogo/signed-tags

Change release-process.md to sign release tags
Merge pull request #3353

1e01f7c Payment request URI syntax changed, from request=... to r=... (Gavin Andresen)