Updated readme again
Updated readme again

Changed a few bits of wording, updated the brew instructions to include all three libraries.
Safari-FIDO-U2F/Safari-FIDO-U2F,Safari-FIDO-U2F/Safari-FIDO-U2F,Safari-FIDO-U2F/Safari-FIDO-U2F,Safari-FIDO-U2F/Safari-FIDO-U2F