Extend REST API with current buffer index (point).
Add start_jedi target to Makefile.
Improve logging settings. Write development log on debug.
Start jedi with --debug option on ert tests.
Use custom start_jedi port on make emacs target.

For avoid conflict with installed company-jedi package.
Implement company prefix API.

CompanyJedi constructor extended with following keyword args:
company_prefix, company_arg, point. New keyword used for evaluate
implied content for jedi call. Fix all unittests for new logic.
Add goto-definition function for python mode.

Maybe used when company menu inactivate.