Switch to handle, split, release 0.2.0.0

[sorki]

• Split slcan and socketcan into public sublibraries

• Migrate to io-classes and switch from MonadCAN typeclass
  to CAN handle (record of functions style):

  data CAN m = CAN
  { canSend :: CANMessage -> m ()
  , canRecv :: m CANMessage
  }
  

• Runners renamed

  • runSocketCAN is now withSocketCAN
  • runSLCAN is now withSLCAN
    to reflect the handle change