add ExperimentSection.description property
reduce number of debug messages when running sections
refactor _parent_context from run_experiment_section

--HG--
extra : amend_source : 6ecbd09a23a3b3035c195147381589f4a5fbf246
refactor _parse_from_section from run_experiment_section
fix bug where parent sections are marked as having started when running demo
workaround for pandas issue 7380
comparing any object to a different type returns False
bumpversion
Added tag v0.2.4 for changeset b4248294b8c7