0.8.6

• Raise informative error if config variables are declared but unavailable
• Update ExpectationsStore defaults to be consistent across all FixedLengthTupleStoreBackend objects
• Add support for setting spark_options via SparkDFDatasource
• Include tail_weights by default when using build_continuous_partition_object
• Fix Redshift quantiles computation and type detection
• Allow boto3 options to be configured (#887)