- Update to 1.4.2:
* C-level:
- simplify pack/unpack code
- fix memory leak in `~` operation (bitarray_cpinvert)
* add official Python 3.9 support
* improve many docstrings
* add DeprecationWarning for `bitdiff()`
* add DeprecationWarning when trying to extend bitarrays
from bytes on Python 3 (`bitarrays(b'011')` and `.extend(b'110')`)
* C-level:
- rewrote `.fromfile()` and `.tofile()` implementation,
such that now the same code is used for Python 2 and 3.
The new implementation is more memoery efficient on
Python 3.
- use memcmp() in richcompare to shortcut EQ/NE, when
comparing two very large bitarrays for equality the
speedup can easily be 100x
- simplify how unpacking is handled
* add more tests
* add `.clear()` method (Python 3.3 added this method to lists)
* avoid overallocation when bitarray objects are initially created
* raise BufferError when resizing bitarrays which is exporting buffers
* add example to study the resize() function
* improve some error messages
* raise `NotImplementedError` with (useful message) when trying to call
the `.fromstring()` or `.tostring()` methods, which have been removed
in the last release