v2.0.0

A complete rebuild of how Packtype works to address a bunch of technical debt:

• Declared types can now be used natively in Python without rendering out a template
• Parameterisation of primitives such as Scalar is now performed using the [...] (square bracket) typing syntax that is common in Python (i.e. Scalar[19] declares a 19-bit scalar type)
• The innards of type declaration now leverage dataclasses to simplify the nastiness of dealing with __annotations__ manually
• Exceptions have been updated through to be more distinct (rather than using assert a lot)
• C/C++ templates have been temporarily removed (they need to be rewritten)