Add a UI

[tmr232]

As nice as it is to have all settings easily stored, it is not too useful without a way to edit them.
In the present situation, every plugin writer needs to create some way of modifying the settings of his own plugin (much like I did with IPM.)

A far better solution will be a GUI to allow easy viewing and editing of all the settings.

Sadly, this means writing a GUI...

[williballenthin]

acknowledged and agreed. i'll take a stab at this in the near future.

[williballenthin]

addressed in 7be8f94