New Enum Derive Type (Enum Return Groups)

[SCDevel]

Ok first off I made this for another project of mine that uses strum and wanted to play around with macros and avoid my other project. so I don't really plan on updating this anymore unless I run into issues with my other project. But anyways I figured you guys/girls might be interested in it so I wrote some documents and am creating this pull request.

I apologize for any "bad" code but I truly only code as a boredom/hobby thing.

Here is a TLDR of what this does. more info can be found in the lib.rs -> EnumGroups() as a doc string and playing in the tests.

TLDR:
Edit (fixed my terrible grammar):
This groups all of the variants by there arguments and generates a struct with variable for each grouped return type wrapped in a Option<T>. each variant auto implements a new .get_groups() which returns the generated struct of types; which should populated with all None except for the one that applies to the variant its called from. that result should be Some(T)