Labbench

Added
- panel function for displaying tables of testbed state in jupyter notebook
- temporarily include log_progress github repo code; need to pin down license situation

Changed
- fixed Localhost.state.time encoding problem for python 3
- fixed database introspection problem for python 3
- fixed contextframe introspection problem for python 3
- fixed argument bug in LogAggregator.observe

Removed

Added
- LocalHost device provides error log and localhost timestamp states
- core.py: "List" state descriptor, to support localhost.py

Changed
- automatically observe localhost time and log data on each database append() using LocalHost in all types of database
- PC timestamp field name is now 'localhost_time'
- relational data directory now has the same path as the master database file (minus the file extension)
- support database logging from device states that return lists or tuples

Removed
- managedata.py: LogAggregator.make_timestamp method (use LocalHost.state.time instead)

"Distant pre-history"