Featurize changes

[ardunn]

Added logger
Refactored featurize_columns to auto_featurize
Prevent missing df keys from failing auto_featurize (just warn via logger)

[ardunn]

@albalu pls merge if you are ok with these changes

[albalu]

It all looks good. I'll merge once the tests are passed.

As a side note, what's stopping us from getting rid of MultipleFeaturizer other than the fact that it is in the paper? It is causing too much hassle in my opinion. Anyone can write a for loop over their list of featurizers and featurize_dataframe that way no?

[ardunn]

@albalu Nothing is stopping us! I liked the simplicity of MultipleFeaturizer but with the caching stuff added it fails a decent amount and the pbar doesn't work right (ie, each featurizer doesn't get its own pbar) so I rarely use it now.

[ardunn]

@albalu I am just going to merge now cuz it is passing tests