Update README.md about reimplented objects

Mention the new Event object and add missing RLock object, and update
the text describing the new objects.

Signed-off-by: Nir Soffer <nsoffer@redhat.com>
Improve README.md formatting

Wrap lines to 80 characters, use markdown code block for the example
usage, and add missing dot in the example code.

Signed-off-by: Nir Soffer <nsoffer@redhat.com>