Eliminate MagicPhpWikiURL forms in favor of new WikiForm plugin.

Eliminate MagicPhpWikiURL forms in favor of new WikiForm plugin.

The problem with the MagicPhpWikiURL forms, is that <form>s are
not inline (HTML) markup, while MagicPhpWikiURLs look like links,
which are inline markup.  The mixing of the two makes for very
messy hackage in the text transformation engines.

(The only place the magic forms were still used in for the
file load/upload and file dump administrative functions.
The WikiForm plugin now produces those forms.)

git-svn-id: svn://svn.code.sf.net/p/phpwiki/code/trunk@1892 96ab9672-09ca-45d6-a79d-3d69d39ca109