initial commit of the custom raspberry_pi externals supporting read/write from digital pins, analog pins (using shield with a mcp3008 A/D converter), and netsend~/netreceive~ optimized for rpi (net objects being copies of work done in the core pd)

fixed cursor inconsistently failing to reflect topmost clickable object while ignoring non-clickable objects that are above topmost clickable object, both on main canvas and inside gop objects.

removed clicks from multitap using variable delay (now has different temporary artifacts that actually sound pretty cool).

fixed long-standing bug where on GOP objects click registered on the first detected object, rather than the one that was visually topmost

added one more k12 object and updated pd.tk to reflect new items in the k12 menu (including new minimum size)

added new abstractions to the K12 module (still need to integrate it into pd-l2ork and add help files)

slowed down the rate of update to avoid choking down the GUI (bumped update of the wii speed from 1 to 25ms)

further cleaned-up ggee/image selection logic (now the selection does not incorrectly pick up on the parent GOP selection, so that when opening subpatcher it does not show up as selected

improved ggee/image to have a default empty image and ensured that its layer ordering is preserved after loading a new image. Finally, made a check for valid images--if invalid format, the image reverts to default empty image included in the ggee.

Pull latest s_midi_alsa.c from mainstream Pd. Removes autoconnect misfea...