Greatly improve monitor info compiled by monitor classes

This will be important for allowing the user to set per-monitor color
profiles, as we need things like a friendly monitor name to display to
the user.
Turn on color management for image windows

A great deal of trial-and-error has been necessary to find how best to
handle color management while accounting for VB quirks like .AutoRedraw.
I think I have finally found the best implementation for both
performance and reliability.

Color management is no longer activated for pdLayers.  This means we can
transfer data between layers (something PD does frequently) without any
color management slowdown.  And, because layers will only ever be in the
sRGB space, there is no loss of color accuracy from doing this.

Image windows now have color management explicitly turned on, and as of
this commit, the default system color profile is applied.  This can
easily be tested by using a test ICC profile (as available here:
http://www.gballard.net/photoshop/pdi_download/index.html#downloads),
specifying it via the Windows Control Panel Color Management dialog,
then comparing PD's rendering of a test image to something like
Paint.NET.  Similarly, you can compare the rendering in PD of a main
image window (color managed) against a preview window in any tool (not
color managed) to see the difference!

Because .AutoRedraw = True can cause a form's DC to change at run-time,
it is necessary to explicitly re-apply color management before every
viewport render.  Performance does not seem to be noticeably impacted by
this, thankfully.