Fix instances of "siteurl" that should use home_url().
Remove unused  $siteurl references.
Use site_url() instead of get_option( 'siteurl' ).
Use admin_url() instead of "siteurl" for admin URLs.
home_url() should include slash when adding query args. Props meloniq
Use get_edit_post_link() for product edit link. Props meloniq
Merge pull request #282 from benhuson/PR_siteurl-homeurl

Use home_url(), site_url() and admin_url() where appropriate.