#1 Add support for DVD-RW

[Greg Woolsey]

I've hacked up my copy of Mythburn to handle DVD-RWs,
but it was some patched, modified tarball I found
somewhere on the web, so I don't have a clean patch to
submit. The changes were pretty easy, I just added an
"erase DVD-RW" checkbox to the options page, and
corresponding code to the main shell script. The dvd
command is "dvd+rw-format -force /dev/dvd" at least on
my Fedora system. Don't know if the device needs to be
configurable.