They're not needed, they are handled by the state management anyway.

We cannot remove this because we still have to load the surface as
RGB. The shader may take care of setting the blue channel to 1.0 now,
but we still get the red and green channels loaded incorrectly if we
don't insert a blue channel before loading.

The RichEditWndProc_common function is big enough already by handling
all the window messages, so moving code to handle a message to its own
function makes the code more readable.

Adds a binary resource that consists of the string "Wine placeholder
BINK resource" padded with zeroes.

Spotted by Andrew Talbot.

Also corrects some related comments.

Based on a patch by Maarten Lankhorst.