WP 3.6 compatibility fixes with slashing, fixes #1584 and #1585

Fixes LIKE escaping to use pods_sanitize_like, fixes calls to
addslashes/stripslashes to use pods_slash/pods_unslash, changed
pods_sanitize to use wp_slash for WP 3.6 compatibility until we get
Pods core properly fixed to support the 3.6 changes to esc_sql now
using a real escape vs weak escape