Add machine learning functions plugin

Add functions to train and use machine learning models (classifiers and
regressors) in Presto. This is currently only a proof of concept, and is
not ready for use in production. Example usage is as follows:

SELECT evaluate_classifier_predictions(label, classify(features, model))
FROM (
    SELECT learn_classifier(label, features) AS model
    FROM my_training_data;
)
CROSS JOIN my_validation_data;
Add missing file
Fix MappedRecordCursor bug
Make TestDateTimeFunctions single threaded
Add varbinary type
Map Hive binary type to varbinary
Add jmx stats for abandoned and canceled queries
Remove unnecessary import
Fix type check in RC binary cursor for varbinary fields
Fix failing unit test
Set datasource on system splits
Add option to disable scheduling tasks on coordinator
Add javax.inject to parent first class list
Improve logging for catalog loading
Extract benchmarks into separate module
Extract native connector into separate plugin

The native connector is now called Raptor and lives in presto-raptor.