Add a default color to chosen results

This fixes https://github.com/harvesthq/chosen/issues/1724#issuecomment-34399579. With no color on `.chosen-results` it defaulted to body text, which is not good if that's anything other than a black. I matched the color to `.chosen-single`.

While doing this I quickly looked at colors and changed two small things. I made `.no-results` lighter, and found that the multiple select input did not need `color: #999` on a separate `.default` style, so I fixed that.