Set a real git config user name/email

Just setting the environment variables does not seem to prevent the
problem of no user config. Hopefully this works...

Fixes #47
migrate to Path::Tiny

This makes a bunch of nicer code

Fixes #45
add/update links in documentation

Fixed a couple wrong docs as well. I imagine a bunch of these are broken
links, but we won't know until metacpan renders them...

Fixes #44
remove unused attribute

The git site uses the deploy store, not a simple dir as I first
imagined.