This fixes the issue where the calculation for the offset of the image
data was incorrect. Instead of just looking at the first byte past the end
of the BITMAPINFOHEADER we now correctly calculate the offset past the
color palette and begin reading the image there. This stops the problems
where sometimes the image looked like it had been shifted, or other cases
where the image colors went retro.
VS 2013 appears to have built-in formatting for C++, so this commit tidies
up the code a bit to fit within those rules.
It also removes a few warnings which the new compiler has shown.
The clipboard code now supports the `CF_DIB` format on the clipboard. When
found, it takes the data and uses GDI+ to convert it into a JPEG. GDI+ was
used because:
* It's on every Windows machine from XP SP0 onwards (Win2k doesn't work).
* It requires linking to a small gdiplus.lib instead of a massive jpeg
library.
* It's a really easy interface to use that interops easily with the
Windows bitmap header information structures.
I think it'd be worth considering this approach for the other screenshot
applications as well, as it'd reduce the jpeg lib dependency and simplify
the codebase.
