Adding cluster progress to the clusters get call, as well as
the cluster provider and template as objects instead of strings.
This is to preserve the structure of these objects when a get
call is made for a specific cluster to keep the apis restful.
Also using java objects instead of manipulating json objects
for those.

Including progress requires adding another column to the
clusters table in order to allow joining on the job number. Since
this makes the getClusterStatuses rpc call useless, removed it.
fix typo.
update changelog.
Merge pull request #430 from continuuity/feature/consistent-nesting

Adding cluster progress to the clusters get call, as well as
Merge remote-tracking branch 'origin/develop' into feature/check-cluster-args-early

Conflicts:
	server/src/main/java/com/continuuity/loom/scheduler/task/ClusterService.java
moving validation code to their respective classes instead of
keeping them all in the cluster service.