Improved comments and code organization
Improved comments
Epic histogram revamp

- Per-channel histogram rendering
- Interface redesign
- Better stats (max channel and value are now displayed)
- Speed optimizations, including look-up tables for luminance
calculation
Minor histogram UI adjustments
More minor histogram UI adjustments

repositioning labels, specifically
Added previewing to the grayscale conversion form

This was one of the final forms to be missing a preview function.  It
also uses a new system for previewing that doesn't require two functions
per filter (a preview and regular one).  Instead, it accepts a
"toPreview" flag and adjusts its run-time parameters accordingly.  This
dramatically cuts down on code maintenance, and it will need to be
mirrored across every other preview-generating form.   <sigh>
Imported grayscale code improvements from tannerhelland.com project

http://www.tannerhelland.com/3643/grayscale-image-algorithm-vb6/
contains optimized versions of PhotoDemon's grayscale code.  Those
optimizations have now been backported in PhotoDemon.  #1 is now
partially complete; I still need to backport the additional grayscale
conversion algorithms (single color channel, decompose) from that
project.
Force immediate image form unload after "No" answer to save confirmation

If this isn't done, the user may be prompted to save this form twice.
Allow grayscale reduction to two colors

The previous minimum was three.  I did this because I'd prefer that the
user user "Black and White Conversion" for converting to two colors, but
hey - if they want to use custom grayscale to do that, who am I to get
in their way?  (Also, the grayscale algorithm already handles two colors
so it's minimal work to enable this behavior.)
Added additional routines for enumerating all controls within a container control
Remove unnecessary routine for enumerating controls within a container control

Turns out that the original function handles this just fine.  Oops!
Implement additional grayscale algorithms from tannerhelland.com project (#1 closed)

PhotoDemon now supplies all the same grayscale converting power as
(http://www.tannerhelland.com/3643/grayscale-image-algorithm-vb6/).  #1
can be closed with this commit.
Require grayscale preview requests to supply source and destination pictures
Minor fixes (comment misspellings, tabstops out of order)
Add "check for updates?" to the INI interface and handler

Step one toward building an automatic updater: complete.

I also redesigned the program preferences interface to match this
change.  Now included is a button that launches a message box that
explains how PhotoDemon does not upload any information as part of its
Internet-related features.
Automatically check for updated software versions

This commit only contains the code for CHECKING for updated software.
It attempts to access an online updates.txt file, extract version
numbers, then compare those numbers against the current app version.

If successful, it launches a blank form.  (Populating that form is next
on the to-do list.)  If unsuccessful, or if the software is up-to-date,
nothing happens.
Update notifier complete; fires automatically on program load

Only thing left to do is add a manual entry to the "Help" menu, then
this is complete!
Added "check for updates" to Help menu

As of this commit, I consider update notification to be 100% complete.
Change "Import from VB Binary file" menu to "...from Visual Basic Binary File...", as not everybody should be expect to know what VB is, if they're just a user of the software.