Adding two example notebooks for jupyter support (+3 squashed commits)
Squashed commits:
[d5e6163] Update dependency versions for spark to lastest 2.x version, and ensure we are pulling from correct maven repos.
[664c77f] Update default values for feature type names for spark command. When using default names with command an error will be produced if you attempt
to register a table with spark sql that contains a '-'
[3edb12a] Add code path for KMeansRunner so it can be run from an existing SparkContext

Fix notebook download command.
Ensure we wait until spark is available to install the kernel.

Ensure jupyter bootstraps are moved into their own generated folder which will put them in a separate folder on s3.