Converts Help's layout to GML, propagates model and icon creation
errors, and switches to the MainWidget-namespace organization
pattern seen in more up-to-date apps like TextEditor to make things
easier to maintain going forward.
This is partially a revert of commits:
10a8b6d411561b67a1ad
Rather than adding the prot_exec pledge requried to use dlopen(), we can
link directly against LibUnicodeData in applications that we know need
that library.
This might make the dlopen() dance a bit unnecessary. The same purpose
might now be fulfilled with weak symbols. That can be revisted next, but
for now, this at least removes the potential security risk of apps like
the Browser having prot_exec privileges.
