Windows GUI: Add option to disable texture filtering to Options menu, since it's missing.
Add ID_OPTIONS_TEXTUREFILTERING_OFF to the int array. Thanks to @unknownbrackets for pointing it out.
Rename "Off" to "Auto", and fix buggy menu.
Simplify loop.
Merge pull request #2583 from thedax/master

Windows GUI: Add option to disable texture filtering in Options -> Texture Filtering