Compromise on Adjustments menu layout

(Begin rant!)

No photo editing software handles this menu well, and I'm beginning to
see why.  Theoretically, the various correction items are all related -
but in practicality, the line dividing one adjustment from another is
nebulous (at best).

Take something simple like "color temperature".  Is it a color or
lighting correction?  What about artistic or scientific?  Common?
Uncommon?  Both?  All of the above?  Depending on your camera or where
you take photos, it's something you'll either never use, or something
you'll use for every damn photo.

Categorization is tough, and I actually quite like PD's latest category
arrangement.  It's far better than Photoshop, GIMP, etc, with a logical
division between items, and a good group count within each menu.  Icons
further help distinguish the various types of adjustments, and we adhere
to PhotoDemon's rule of never going more than two menus deep.

The unfortunate downside of any good menu organization is that the use
of categorization pushes clickable menu items one level deeper.
Photoshop does this by default (seriously, their Image menu is a debacle
- the entire Adjustments menu is a sub-menu, with no conceivable
organization!), and GIMP has a menu organization that I assume no one
has ever considered.  (Why does it go Color Balance, Hue Saturation,
Colorize, Brightness/Contrast...?  Why is Posterize anywhere on that
list?  Why are auto options HALFWAY down the menu?)

Paint.NET and most smaller photo editors ignore organization simply
because they have so few menu items, but PD's breadth of tools requires
something better.  I think yesterday's reorganization was a big step
forward.

Today is simply a refinement of it, with the most common tools (by my
research) listed doubly: within their respective sub-category, and
pinned at the top of the base Adjustments menu for easy access.  To be
fair, there is no such thing as "most common tools" for every one - the
nature of photography means every photographer has unique needs - but I
think a few "staples" of image correction are worthy of being set aside,
and that is what this commit attempts to solve.