Deliver alpha 12 branch content.
- Fix memory leaks in plum-boost.
- Fix bitfield representations when embedded within a structure or another bitfield (previously, they lacked the class name and just showed fields).
- Allow pack method to be overridden in structure definitions (previously metaclass constructed one any that were supplied in class definition).
- Swap
parents
anddump
positional arguments in__unpack__
method to improve look of code that overrides this method.