hgview #146808 handle revision filtering from the command line on startup [open]

The idea would be to allow launching hgview in "filter mode", similar to a filtered log. E.g.:

hg qv -r 'file("hgviewlib/*") and author("alain")'
hg qv -r 'branch("stable")'
prioritynormal
typeenhancement
done in<not specified>
closed by<not specified>