Updated HTML editor/display control

[Tim Anderson]

I've updated the HtmlEditor here:

http://www.itwriting.com/htmleditor/index.php

This is a free-to-use C# control which hosts mshtml as an Active Document.
Main changes are improved focus handling, fixed a bug in document cleanup,
added user-friendly properties and methods to wrap the most useful
mshtml commands. Better declaration of IOLECommandTarget.Exec means
that IDM_COMPOSESETTINGS now works, although having tried it
I don't like it much because of course it inserts a FONT tag.

Thanks to the efforts of others all the standard keyboart shortcuts now
work, such as Ctrl-A for Select All, and even Ctrl-F for the Find dialog.

I also experimented with a version that does not use the mshtml PIA.
I got this working but was surprised to find little benefit. Faster loading
time and reduced mem. usage (of about 2MB) but that's it. The 2MB
saving may seem a lot, but that's in the context of a typical winform app
unfortunately it's not that much. So I'm sticking with the PIA for the
moment as it's a lot more convenient, especially if you need to work with
the mshtml DOM.

Tim