Use SWFUpload on importer tools

[beaulebens]

Attached is a patch that does the following:

• Enables support for the lj-user tag, and creates a link to that user's homepage (with class="lj-user" for styling purposes) - fixes #5840
• Converts lj-cut tags to <!--more--> tags and removes all but the first one
• Provides the SWFUploader for the uploading files (impacts Blogware, MovableType/TypePad, RSS and WordPress importers as well)
• Adds some user-friendly instructions on how to export from LJ properly
• Removes the use of /e in preg_replace() for livejournal.php as detailed in #8689
• Adds the title of the post to the output in the RSS importer as well (since all the others do that)

This patch was developed based on r10331

Fixed issue when cleaning up upper-case tags.

Updated for [10340]

Ignoring the fact that the LiveJournal importer has been completely rewritten, what do the devs/etc think of the SWFUploader part of this patch?

If it's worth it (the main benefit being that it adds the progress bar to the upload?), then I'll make a new patch that just handles that part on the current trunk.

Definitely something nice to have, but 2.9 will be changing media and upload stuff so we should table this until then.

Maybe use now Plupload, see #18206.