Change package names from com.hpcloud to monasca.common

To have sensible package names this required changing the model package
names

Change-Id: I7ce96c4574d1e851f64ee6235324bb12fd01ac78
Changes done to fix monasca-thresh issues with string instead of double.
Merge commit '2b725ec5e240b663ac930f8190149579767cd94f'