chg: dev: use simplejson for speed if possible gh-231
chg: dev: remove call_log decorator by default gh-231
chg: dev: check for self-loops in validator
chg: dev: remove creating a logger on each instantation gh-231
chg: dev: option to disable vis for gh-231
chg: dev: add profiler for gh-231
chg: dev: more informative logging
chg: dev: remove self-loops if identical node names
chg: dev: drop log level back for gh-231
chg: dev: continue work on renderer for gh-230