Updated edit_post form creation.

Update queries for various article elements, remove footer, leave keywords
as it was before, and append header to form instead of just title &
keywords.
Get variables from $_POST first for handling new_post form

Use these in an associative array to validate input. Need to use strip_tags()
prior to validation because otherwise certain ones (keywords) to not match
pattern.

Disable edit_post submission and just respond by logging the request for
debugging (needs to be updated to better handle keywords)
Update handling of edit_post form

Use a slightly complex combination of urldecode(), trim(), strip_tags(), and
str_replace() to correctly get tags from form for keywords.