Add information about librt and OpenBSD to the FAQ
Add info about Backspace and Delete to the FAQ
Add info about Backspace and Delete to the FAQ

Here is a modest attempt at cleaning it up a little bit. I changed a
few phrases that seemed awkward, but I think the content is the same.

--
Wolfgang Corcoran-Mathe

Signed-off-by: Roberto E. Vargas Caballero <k0ga@shike2.com>
Merge branch 'master' of http://git.suckless.org/st