Release 0.11.1

Changes:

• Accelerated formula evaluation by ~15%
• Improved model application interface
• Improved compilation time for building GPU version
• Better handling of stray commas in list arguments
• Added a benchmark that employs Rossman Store Sales dataset to compare quality of GBDT packages
• Added references to Catboost papers in R-package CITATION file (issue #488)
• Fixed a build issue in compilation for GPU
• Fixed a bug in model applicator
• Fixed model conversion (issue #533)
• Returned pre 0.11 behaviour for best_score_ and evals_result_ (issue #539)
• Make valid .dist-info/RECORD in python wheel (issue #534)