[PD] deken install user experience

[Hans-Christoph Steiner]

I'm just trying deken for the first time, awesome piece of work!  I'd
like to find a little time to contribute to it, to smooth out the user
experience for newbies.  I can see there are all sorts of use cases for
all of the install options that it currently provides, but it is pretty
confusing for most people who just want to use a library. I don't want
to step on any toes, so I thought I'd throw out some ideas here:

* hide all incompatible library version by default (e.g. hide OSX and
Windows versions on GNU/Linux)

* by default, install into user's pd externals folder without any prompt
(~/pd-externals, etc)

* add "Advanced Mode" or "Expert Mode" that shows the current user
experience

* remember which mode the user has selected across pd starts (e.g. make
a pref)


.hc