Add new thanks to About dialog
Batch wizard: fix potential image preview errors

Thanks to GioRock for reporting
Paste: fix for images coming from IE

When copying images from GD IE, the accompanying clipboard text may
include malformed HTML, which would cause PD to fail when parsing for an
img tag (as PD prefers to download an image itself, rather than take the
clipboard copy, if at all possible).

Fortunately the fix is simple; PD no longer assumes that the
accompanying HTML is to spec.  Thanks to Gio for reporting.