First pass at abstracting the WP Remote CLI commands to a new pattern
Fields aren't needed here any longer
Basic `remote-core` commands

Closes #7
Move `remote site-list` to `wpr-account list-sites`
Move `site-add` and `site-delete` to `wpr-account add-site` and `wpr-account delete-site`
Move `site-log` to `remote-site list-history`
Increase default timeout
Move site refresh to `remote-site refresh`
Remove the rest of this becuz we don't need it anymore

Except for the theme commands, but we'll get to those later
Merge pull request #11 from humanmade/new-pattern

Refactor