Setup the enforcer plugin
Merge pull request #142 from bigdatagenomics/matt-maven-enforce

Enforce Maven and Java versions
Moving createSparkContext into core

- There are some specific ways that ADAM needs to setup the spark
  context, and can be used if only core is referenced
Updating Changes files
Merge pull request #148 from genomebridge/moveSparkContextCreation

Moving createSparkContext into core