miurahr/py7zr: Decryption support

Added Test: SevenZipFile.archiveinfo() for various archives. Test: extraction of LZMA+BCJ archive become fails as marked known issue. Support deflate decompression method. Changed Update documents and README about supported algorithms. Re-enable coverage report. Refactoring SevenZipFile._write_archive() method to move core chunk into compression module Worker.archive() method. Update calculate_key helper to improve performance. Introduce zero-copy buffer helper. Change decompressor class interface change max_length type to int and defualt to -1. Update decryption function to improve performance. Fixed Fix SevenZipFIle.archiveinfo() crash for LZMA+BCJ archive.(#100) Fix SevenZipFile.test() method defeated from v0.6b2 (#103) Fix SevenZipFile.solid() method to return proper value. (#72,#97