Add post validation for redirection page, so that any URL outside of own forum posts will be mark as invalid (Refer to the case of @findozor here: https://xenforo.com/community/threads/d-c-style-link-proxy.185180/post-1580681)
Correct the phrase "continue" (Refer to the case of @beansbaxter here: https://xenforo.com/community/threads/d-c-style-link-proxy.185180/post-1677517)
Improve code for encoded URL builder
URL blocker will be added in the upcoming version!
