Integrate or break dependency on spylon package

[parente]

maxpoint/spylon is used for configuration purposes in the %%init_spark block and to create the SparkContext from that config. We're uncertain as to whether we're going to keep maintaining the spylon package as a separate entity or not. Either we should break ties with it and go back to using the plain old SparkConfig object with strings, or merge the pieces that support attribute dot-notation and autocomplete into spylon-kernel.

[mariusvniekerk]

A reasonable amount of the spylon scala utilities aren't that needed anymore due to improvements in py4j as well.