Removed all trailing whitespace.

I've got fed up with my text editor and git disagreeing on where there should be whitespace, and being stuck in the middle making manual corrections all the time. This commit removes all existing trailing whitespace, so I'll be able to turn on "strip trailing space" in my editor, keeping git happy in the future without intermixing whitespace changes with actual code changes (as would happen without this one-off fix).

If everyone else could turn on the "strip trailing space" feature in their editor of choice, that would be grand.