Add README.md

It's currently a statement of intent
Add the antigen handler for zsh

Just makes it slightly easier to install.
Add framework for easy-ln command
Update docs

Not all forms are the 1st form, and the markdown for the invocation is
wrong.
Set up handling framework

Switched to zsh because I really really like zshparseopts (and other
things).
Implement core methods

This now works.
Add link and antigen install command
Merge branch 'release/1.0.0'