rarfile v3.2

New features:

• Support unar as decompression backend. It has much better support for RAR features than bsdtar. [#36]
• Support SFX archives - archive header is searched in first 2MB of the file. [#48]
• Add HACK_TMP_DIR option, to force temp files into specific directory. [#43]

Fixes:

• Always use "/" for path separator in command-line, gives better results on Windows.

Cleanups:

• Drop module-level options from docs, they create confusion. [#47]
• Drop support for Python 2 and 3.5 and earlier. Python 2 is dead and requiring Python 3.6 gives blake2s, stdlib that supports pathlib, and ordered dict without compat hacks.
• Replace PyCrypto with PyCryptodome in tests.
• Use Github Actions for CI.