*) Improve regex detection. Fixes 17, 23
*) Add aarch64 wheels (issue 24, 25, contributed by odidev)
*) Add tests to source distribution (issue 20, contributed by dvzrv)
*) bytearray input now produces bytearray output
*) Update python support: 2.7, 3.6+
*) Emit the correct env var name in the warning message if the compilation of
the C implementation fails.