Fix deprecation warnings with python 3.8.1

v1.1.4

Fix deprecation warnings with python 3.8.1

Fixing the `@unique_bits` decorator

v1.1.3

Fix @unique_bits

Fixing len() for abstract flags classes

v1.1.2

fixing len() for abstract flags classes

Smaller fixes

• Fix: added the @unique and @unique_bits decorators to the __all__ list of the flags module.
• Fix: testing abstract flags classes for truth value caused the following exception:
  AttributeError: type object 'Flags' has no attribute '__all_members__'

Added full documentation to README.rst and lots of small code changes

• Extended README.rst with full documentation. Before it contained only a "Quick Overview" section.
• Added Flags.__dotted_single_flag_str__.
• The Flags.data property returns UNDEFINED for special flags and flag combinations.
• Added the __pickle_int_flags__ class attribute that can be set to True in order to force pickle to save
  the int representation of flags instead of the default to_simple_str() representation.
• Added the @unique_bits decorator that can be used to forbid overlapping bits between the values of flags.
• Added the @unique decorator that can be used to forbid aliases in a flags class. (An alias is a flag that
  has the exact same value as a previously declared flag.)
• Added __repr__ for flags classes.

Minor fixes to the initial distribution

Fixed README.rst, the pypi distribution contained some garbage from my local README.rst version.

Initial release on pypi

README.rst contains only a minimalist quick intro but the module is feature complete and well tested.