Implement persistence/restoring of print spooler state.

1. Implemented the persistence and restoring of the print spooler state.
   The print spooler state is saved as an XML on every print job change
   and is restored when we bind to the spooler. The system does not
   unbind from the spooler until the state persistence completes. We
   are now storing the entire state, i.e. all print jobs, when a single
   one changes. This is not optimal but we are not expecting to have
   many such at the same time, so for now we err for simplicity of
   implementation.

2. Enforcing a non-empty print job name.

3. Hidden the STATE_CREATED print job state which should never be visible to a
   client since this is the state of a print job during construction, i.e. the
   print dialog is up and we are doing back and forth with the app.

4. Fixed some PrintAttributes APIs that were incorrectly taking in a PackageManager
   instance.

5. Updated the PrintSpooler build file due to splitting the framework into multiple
   jars.

Change-Id: I52c88eaa1ec9c64920359cc143c79832a4c3d25b