#99 NFS mount 'noac' option

[Glenn Burkhardt]

There should be a way to add the option 'noac' for NFS
mounts. In fact, there should be a way to add any of
the supported NFS mount options. Perhaps if it's too
much to add a checkbox, there could be a line edit
widget that allows entry of arbitrary option strings.
Unfortunately, the next step after that would be to
validate the user entry, at which point a checkbox for
each option becomes more attractive.