Universal breakout footprints.

*   `dil` generalized to `dil_to`. Footprints can now be generated in subdirs of `footprints`, and the resulting embedded URL (to the github project) should still be correct.
*   28-pin "universal" footprints (footprints extended inward to accommodate narrower devices with the same pitch) are generated for SOIC and SSOP.
Generic 28-pin device for breakout schematics.