Pre-seeded device support and workaround for pyserial packaging bug

All pyserial releases (.whl install) newer than 3.2.0 appear to contain an erroneous aio.py file which is breaking things. python-insteonplm now pins to pyserial 3.2.0 specifically until that project has a chance to correct the problem.

Also included @lanrongwen's work to allow pushing devices into activity even if they don't exist in the PLM's IPDB.