gitignore changes to make my life easier

[CarlKenner]

[Codes4Fun]

Honestly Carl, I want to think about this one. I know you're probably using cmake the way the original readme says with the batch files? But you're not taking advantage of cmake if you're putting you're build directories inside your source directory, it doesn't make sense with cmake when you don't have to, I have several floating build directories as well, one with openal and one without, for example. It is worthwhile and shouldn't be that hard to get cmake to use a separate directory for builds, I use it in a lot of projects myself even places I've worked in the past have used it.

I'd much rather update the visual studio scripts, or even better, update the readme so people learn more about cmake.