- Refactored `experiments` module to remove unnecessary child processes,
and greatly simplify ablation code. This should fix issues 73 and 49.
- Deprecated `run_ablation` function, as its functionality has been folded
into `run_configuration`.
- Removed ability to run multiple configuration files in parallel, since
this lead to too many processes being created most of the time.
- Added ability to run multiple ablation experiments from the same
configuration file by adding support for multiple featuresets.
- Added `min_feature_count` value to results files, which fixes 62.
- Added more informative error messages when we run out of memory while
converting things to dense. They now say why something was converted to
dense in the first place.
- Added option to `skll_convert` for creating ARFF files that can be used
for regression in Weka. Previously, files would always contain non-numeric
labels, which would not work with Weka.
- Added ability to name relation in output ARFF files with `skll_convert`.
- Added `class_map` setting for collapsing multiple classes into one
(or just renaming them). See the
[run_experiment documentation](http://skll.readthedocs.org/en/latest/run_experiment.html#input) for details.
- Added warning when using `SVC` with `probability` flag set (2).
- Made logging much less verbose by default and switched to using
`QueueHandler` and `QueueListener` instances when dealing with
multiple processes/threads to prevent deadlocks (75).
- Added simple no-crash unit test for all learners. We check results with
some, but not all. (63)