Agilkia

Added
- Added clustering and visualization of clusters using TSNE.
- Added TraceSet.with_traces_split and with_traces_grouped_by methods to support some common cases.

Changed
- Major refactoring to use class Event, instead of just dict.
- Also started using mypy type checker and removed most type errors.

Added
- Added initial support for smart test generation, using ML action prediction model.
- Add username + password support when interacting with a web service.
- Added save_to_arff method to support the StackedTrees tool from Gilles Bisson.
- Added traces_to_pandas to convert to a Pandas DataFrame. Includes action, inputs, and output status and errors.

Changed
- Switched to MIT license and added more docs.
- Moved action_chars into meta-data.
- Implemented some JSON-trace-version upgrade code, so older data files are read correctly.
- Major refactoring of lists-of-list-of-events into TraceSet and Trace objects, with GDF-like meta-data.
- Color non-zero status results red in trace_to_string to make them stand out.