pycrc 0.7.5 released

• The table-driven algorithm can handle widths that are not byte-aligned as well as widths less than 8.
• Removed half-baken and confusing --direct option. Closes issue 2938846.
• Code clean-up; the generated C code should no more generate warnings about unused variables.

Version 0.7.5 introduces a C/C++ API change: this version introduces the additional (internal) parameter crc_shift in the crc_cfg_t structure. This variable is used by the table-driven algorithm when the width is not defined during code generation. This variable is zero if the width is >= 8.