all: Move into Organization

[DeedleFake]

The project's coming along. It's really buggy still, but it's actually kind of usable as well. As part of making it a bit more 'professional', I'd like to move the repository into a GitHub organization, probably named wdte. Once this has been done, the repository should be split into a number of repositories. The current plan is as follows:

• wdte/wdte: The base package. Will also contain auto, scanner, ast, cmd/wdte, and res. Probably repl, too.
• wdte/axiom: The standard library.
• wdte/pgen: cmd/pgen. See cmd/pgen: move into separate repository #126.