Fix version illegal format

https://github.com/milkypostman/melpa
has guidelines for versions. They are here:

http://marmalade-repo.org/doc-files/package.5.html

and they state that:

The only required header is Version, the value of which must be a
series of numbers separated by periods that identify the package's
version.
Add project Url header

Avoided re-specifying it in the long description
Change versioning scheme to incremental number

I'm worried using a date might bring with it unnecessary busywork as
features may start on a given day and get finished on another. We'll
see how this goes.