Add a 'distribution' module to create assemblies

o Moves the maven-assembly-plugin from adam-cli to the
  new distribution module
o Updates the adam-submit and friends to work from source
  or binary distributions
o Generates docs and adds them to the distribution
o Adds LICENSE, NOTICE.txt, CHANGES.md, etc to distribution
Merge pull request #509 from massie/distro

Add a 'distribution' module to create assemblies
Updated CHANGES.md in prep for 0.15.0 release
Small update to documentation builder
[maven-release-plugin] prepare release adam-parent-0.15.0
[maven-release-plugin] prepare for next development iteration
[maven-release-plugin] rollback the release of adam-parent-0.15.0
Remove docs from distribution
[maven-release-plugin] prepare release adam-parent-0.15.0
[maven-release-plugin] rollback the release of adam-parent-0.15.0
[maven-release-plugin] prepare release adam-parent-0.15.0
[maven-release-plugin] rollback the release of adam-parent-0.15.0
[maven-release-plugin] prepare release adam-parent-0.15.0
[maven-release-plugin] prepare for next development iteration
[ADAM-462] Coverage region calculation

This commit includes an new class, Coverage, which contains methods for
calculating coverage RDDs from RDDs of Region values.

Also included is a helper class, the PairingRDD class, which calculates
simple 'sliding' and 'pair' methods on sorted RDDs using the
"zipWithIndex trick."

(Joint work with Carl Yeksigian.)