Sherlog

- Project dependecies versions are not strictly fixed anymore

- Sherlog now creates functions in DB within the defined schema and not in public schema
- Added new parameter to client config main section. If 'dummy' is true, then no Redis handler
will be attached to the logger. It may be a good idea during development, when you don't
want to spam logs to Redis instance and DB while debug locally but still want to keep your
code base as if Sherlog is there.

- Fixed issue with log messages that contains formatting symbols such as '%' or {}
- format_style kwarg was removed from the sherlog.set_logger() signature

- Fixed critical bug in worker

- Few fixes on Python 2.7 support (unicode issue, stack_info key error)

- Sherlog is now compatible with Python 2.7 (therefore type annotations in source code removed)