data validation (microsoft#45)

* pickle the AutoML object

* get best model per estimator

* test deberta

* stateless API

* prevent divide by zero

* test roberta

* BlendSearchTuner

* delta time

* reindex columns when dropping int-indexed columns

* test drop columns and small training data

* param set for ensemble builder

* fillna on copy

Co-authored-by: Chi Wang (MSR) <chiw@microsoft.com>

Fix bug in NNI tuner (microsoft#34)

* fix bug in nni tuner

* Update version.py

Co-authored-by: liuzhe <zhe.liu@microsoft.com>
Co-authored-by: Chi Wang <wang.chi@microsoft.com>

v0.2.6 (microsoft#32)

* xgboost notebook

* finetuning notebook

* finetuning test

* experimental nni support

* support nested search space

* log file name

* record training_iteration

* eps

* reset times

* std set to default step size if 0

v0.2.5 (microsoft#30)

* test distillbert

* import check

* complete partial config

* None check

* init config is not suggested by bo

* badge

* notebook for lightgbm

Merge pull request microsoft#28 from microsoft/v0.2.4

v0.2.4

None check

v0.1.3 Set default logging level to INFO (microsoft#14)

* set default logging level to INFO

* remove unnecessary import

* API future compatibility

* add test for customized learner

* test dependency

Co-authored-by: Chi Wang (MSR) <chiw@microsoft.com>

Update README.md