ALL: save a default profile on quit, and load it on start.
     which stops me (and everyone else) from making common changes
     on startup.

     The only time this might cause a problem (and still needs to be
     tested, is when you start things, turn it off, swap cards (and
     and therefor which plugins are active).

Signed-off-by: Robin Getz <Robin.Getz@analog.com>