adding upgrade code for upgrading from 0.9.7 to 0.9.8.
Will keep a set of codecs for serializing/deserializing current
objects, and a separate set for converting between versions.
Switched to use guice injection to create the codec everywhere.
adding apis and store for provisioner information, such as the
number of workers running on each provisioner for each tenant.
removing unused code with provisioner status and assign time, and
adding a convenience function for getting a db connection with
auto commit on since thats the vast majority.
fixing heartbeat and expire bugs, and adding more logging.
mock multitenant provisioner for testing purposes.
adding more unit tests.
add documentation for superadmin provisioner apis and changelog.
update changelog with upgrade script.
adding docs for config settings for provisioner requests and
doing some cleanup to simplify building the http client.
just remove the tenant completely from the heartbeat if the live
worker count drops to 0 instead of sending it with a count of 0.
Merge remote-tracking branch 'origin/develop' into feature/db-migration

Conflicts:
	server/src/main/java/com/continuuity/loom/http/handler/LoomClusterHandler.java
	server/src/main/java/com/continuuity/loom/scheduler/CallbackScheduler.java
	server/src/main/java/com/continuuity/loom/scheduler/ClusterScheduler.java
	server/src/main/java/com/continuuity/loom/scheduler/JobScheduler.java
	server/src/main/java/com/continuuity/loom/scheduler/SolverScheduler.java
	server/src/main/java/com/continuuity/loom/scheduler/task/ClusterService.java
	server/src/main/java/com/continuuity/loom/scheduler/task/TaskService.java
	server/src/main/java/com/continuuity/loom/store/cluster/SQLClusterStoreService.java
	server/src/test/java/com/continuuity/loom/http/LoomClusterHandlerTest.java
	server/src/test/java/com/continuuity/loom/scheduler/ClusterCleanupTest.java
	server/src/test/java/com/continuuity/loom/scheduler/SchedulerTest.java
	server/src/test/java/com/continuuity/loom/scheduler/SolverSchedulerTest.java
Merge remote-tracking branch 'origin/develop' into feature/provisioner-apis

Conflicts:
	server/src/main/java/com/continuuity/loom/common/conf/Constants.java
	server/src/main/java/com/continuuity/loom/common/queue/guice/QueueModule.java
	server/src/main/java/com/continuuity/loom/scheduler/JobScheduler.java
	server/src/main/java/com/continuuity/loom/scheduler/task/ClusterService.java
	server/src/test/java/com/continuuity/loom/BaseTest.java
	server/src/test/java/com/continuuity/loom/http/LoomServiceTestBase.java
pull request feedback.  Removing JsonSerde since its just used to
get its underlying Gson, so just binding Gson directly. Refactored
a bit so that database queries are performed by a separated
DBQueryExecutor class that gets its gson injected so that we are
not passing gson around in every method call.

Also adding version to the upgrade tables script.
adding renamed file.
pull request changes.  Adding more comments and javadocs. Also,
make sure a tenants workers have been set to 0 before deleting it.
This is to make it clear to the caller the behavior of the delete.
No additional tasks will be performed for the tenant since it has
no workers.
Merge remote-tracking branch 'origin/develop' into feature/provisioner-apis
more pull request changes. Removing unused code, adding more
comments and moving provisioner timeout logic to its own thread
so that the TenantProvisionerService can be used everywhere
without starting/stopping.
stop service before exiting.
Merge pull request #258 from continuuity/feature/db-migration

adding upgrade code for upgrading from 0.9.7 to 0.9.8.
Merge remote-tracking branch 'origin/develop' into feature/provisioner-apis

Conflicts:
	CHANGELOG.md
	server/src/main/java/com/continuuity/loom/codec/json/JsonSerde.java
	server/src/main/java/com/continuuity/loom/http/handler/LoomSuperadminHandler.java
	server/src/main/java/com/continuuity/loom/runtime/LoomServerMain.java
	server/src/main/java/com/continuuity/loom/store/entity/SQLAdminEntityStoreView.java
	server/src/test/java/com/continuuity/loom/BaseTest.java
	server/src/test/java/com/continuuity/loom/http/LoomSuperadminHandlerTest.java