Lab

Lab
* Use line buffering for run.err files.

Downward Lab
* Preserve line breaks for error logs in tables.
* If an error log in a table has more than 100 lines, omit surplus lines from the middle of the log.
* Always print the number of runs with unexplained errors when generating any type of report.

Lab
* Test Lab on Python 3.8.
* Use active Python version to call run files in local experiments.

Downward Lab
* Support Fast Downward Git repos (Patrick Ferber).

Lab
* Deprecate support for Python versions 2.7 to 3.5.
* Allow only a single aggregation function for ``Attribute`` objects.
* If there is only a single HTML table, show it when the page loads.
* Remove broken ``--log-level`` command line parameter. You can call
``tools.configure_logging(logging.DEBUG)`` to enable debug messages instead.
* Pass old hard memory limit when setting soft memory limit.

Downward Lab
* Scatter plots:

* Add *relative* parameter for drawing relative scatter plots.
* Draw points for algorithm pairs with missing values on axis boundaries.
* Allow drawing negative values on linear and symlog axes.
* Remove *xscale* and *yscale* parameters in favor of a new *scale* parameter.
* Fold ``PlotReport`` class into ``ScatterPlotReport``.
* Simplify code by letting Matplotlib compute axis limits automatically.

Lab
* Upload to PyPI. Install Lab and Downward Lab with ``pip install lab``.
* Add support for running Lab in Python virtual environments (Guillem).
* Parser scripts don't have to be executable anymore, but they must be Python scripts.

Downward Lab
* Abort if two algorithms are identical, i.e., use the same revision, build config and commandline options.
* Scatter plot report: include tasks for which both algorithms have no data if ``show_missing=True``.