Add notes on how to cut a release.

Release 1.4.2

Includes a few fixes to the can_logger configuration.
Tests that require CAN hardware are now skipped by default.

 merge tag adding and type-checking

Added install instructions

Added extra metadata to setup() call in setup.py

Tweaked header comment in dat2tdv.py

Removed default "UNKNOWN" version identifier

Moved get_version_number function from pycanlib into separate hgversi…

…onutils package

Fixed NameError when creating received CAN message

Added deprecation message to xml2tdv.py