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* Removes coverage because it is not really supported for Cython modules.
* Automatically generates intbitset documentation by using Sphinx automodule
functionality.
* Overall, amends documentation to be compatible with reStructuredText.
* Amends .update() and corresponding methods to accept also non-intbitset
objects, such as lists or sets of integers respecting the set interface.
* Raises TypeError rather than terminating current process with a segmentation
fault when None is used on the left side of an operation with an intbitset.
* Initial release of Docker configuration suitable for local developments.
* No longer returns self in fastload().
* Stops using `-march=native` for compilation, because it makes the compiler
to optimize the code for only the currently used processor.