Support rar5 archive format
- Refactor parsing out from main class, with shared code
- RARv5 RarInfo will fake most existing fields to be
compatible with current RARv3 fields, eg: .compress_type,
.flags, .host_os. This makes internally some things
simpler, hopefully for users as well.
Incompat:
- PATH_SEP is now '/' by default. It's default in RARv5
and in zipfile.
Cleanups:
- Remove NEED_COMMENTS option, comments are always extracted.
- Remove UNICODE_COMMENTS option, they are always decoded.
- Remove USE_DATETIME option, .date_time is always tuple,
mtime, ctime, atime, arctime are always datetime objects.
- Bunch of random code cleanups