Minor Release 0.6.8

0.6.8 (2016-01-14)

• Feature: Added automatic conversion of pandas datastructures in the
  custom info dict to json-format in the MongoObserver.
• Feature: Fail if a new config entry is added but it is not used anywhere
• Feature: Added a warning if no observers were added to the experiment.
  Added also an unobserved keyword to commands and a
  --unobserved commandline option to silence that warning
• Feature: Split the debug flag -d into two flags: -d now only disables
  stacktrace filtering, while -D adds post-mortem debugging.
• API change: renamed named_configs_to_use kwarg in ex.run_command
  method to named_configs
• API change: changed the automatic conversion of numpy arrays in the
  MongoObserver from pickle to human readable nested lists.
• Bugfix: Fixed a problem with debugging experiments.
• Bugfix: Fixed a problem with numpy datatypes in the configuration
• Bugfix: More helpful error messages when using return or yield in a
  config scope
• Bugfix: Be more helpful when using -m/--mongo_db and pymongo is not installed