Adding xlarge for 15GB machines on Joyent/Rackspace
add superadmin apis for managing tenants.  Added a db table for
tenants and did some refactoring so common db operations and
generation of ids can be re-used.
Adding default_modules to apache to match the recipe defaults
Adding perl, php5, and python modules
Add ssl to default_modules
Update description
fix incomplete refactoring, cleaning up tenant APIs and
make sure everything that needs to be started is started.
edge case around missing tenant ids.
correcting doc inaccuracies and ambiguities.
Merge pull request #239 from continuuity/feature/superadmin-apis

Feature/superadmin apis
checkstyle fixes.
Merge pull request #242 from continuuity/feature/fix-checkstyle

checkstyle fixes.
Adding tenant to stores and APIs. To do this, introducing the
concept of an Account to keep track of all user information, and
views for the cluster and entity stores. Views are per account,
and only allow access to parts of the database that can be
accessed by that account.
Include automator and provider types in the export and import
calls.
check for script instead of shell
initial proof of concept with threads
pull request feedback.  Moving node, job, task calls out of
the ClusterStoreService and putting it in a ClusterStore class
that is able to see the full store.
remove unused imports.
Merge pull request #245 from continuuity/feature/tenant-in-stores

Adding tenant to stores and APIs. To do this, introducing the
Created a QueueGroup that manages per-tenant queues of different
types, such as per tenant solver queues, per tenant task queues,
etc.  Also did some cleanup around unused code that would timeout
elements in queues. It is no longer scalable to use a thread for
each queue for cleanup purposes.