python: Import improved python bindings.

This commit imports the python bindings from:
    https://github.com/poljar/python-olm



The bindings are imported at commit c44b145818520d69eaaa350fb95afcb846125e0f

Minor modifications were made while importing:
    - Removed travis config
    - Removed Arch Linux PKGBUILD
    - Removed the html docs, they can be rebuild by running make html in
      the docs folder
    - Slightly modified the README

The new bindings feature some improvements over the old ones:
    - Python 2 and 3 support
    - Automatic memory management
    - Automatic memory clearing before it is freed
    - Type signatures via the python typing module
    - Full test coverage
    - Properties are utilized where it makes sense (e.g. account.id)

Signed-off-by: Damir Jelić <poljar@termina.org.uk>