Screen Capture: fix some GDI leaks
Splash screen: new look for 6.6

Minimalism is the name of the game going forward, and the less time the
splash screen is displayed, the better.  As part of that, my general
goal is to draw less attention to the splash screen.  (In fact, I'd be
happy if the user doesn't even notice it.)

Besides a new, lighter look, load progress is now conveyed via a
progress bar instead of text.  Everything but the program logo is
rendered dynamically, at run-time, which limits me a bit (because I
don't have a GDI+ font object written yet), but this is good enough for
6.6's release, I think.

I'm not really sure what to do with the still-old-looking About dialog
just yet, but it's on my to-do list.  High-DPI has also not been tested,
because I need to reinstall Windows 8 on my MBP.
pdTextBox: fix Alt+# character entry for non-surrogate characters

Fix one thing, break two more.  :/