`wp remote theme-delete` to delete a theme from a site.
Implement `wp remote theme-install`
Support `--version` when installing a theme.
When an action is successfully performed, let the end user know.
Implement `wp remote theme-activate`
Implement `wp remote theme-update`
Any time we perform a changing action to a site, let's refresh the site data.

Refreshing the site data is an annoying second step otherwise.
Revert 7332cc9. WP Remote API is responsible for this.
Corresponding commands for installing, activating, deactivating, updating, and uninstalling plugins
Merge pull request #4 from humanmade/theme-plugin-actions

Theme & Plugin actions