Major changes
* MAINT documentation (nearly every part was improved and extended,
including installation, examples, API).
* ADD EPILS as mode (modified version of ParamILS).
* MAINT minimal required versions of configspace, pyrfr, sklearn increased
(several issues fixed in new configspace version).
* MAINT for quality scenarios, the user can specify the objective
value for crashed runs
(returned NaN and Inf are replaced by value for crashed runs).
Minor changes
* FIX issue 220, do not store external data in runhistory.
* MAINT TAEFunc without pynisher possible.
* MAINT intensification: minimal number of required challengers parameterized.
* FIX saving duplicated (capped) runs.
* FIX handling of ordinal parameters.
* MAINT runobj is now mandatory.
* FIX arguments passed to pyrfr.