Pycallflow

Added the -o entity_flow_graphs batch image creation feature

Added clean up functions:

--suppress_calls_to_init
--match_to_file
--clean

Improved visibility when using select_entity_id

This is the initial release of pycallflow. There have already been some minor patches but the main README covers the details.

**Full Changelog**: https://github.com/richmr/pycallflow/commits/v0.0.4