Do not stringify null values in configs
allow null values to pass through the JSON stringifier
Update the tests to test for null values sent for websocket calls
Removed no longer needed cleanUpJSON method
Move status bar to the correct location.
Dropped "Add Units" header.
Merge pull request #667 from kadams54/move-health-bar-2

Move status bar to the correct location.

Fixes bug: https://launchpad.net/bugs/1379653
Merge pull request #664 from hatched/null-config-values

Send null values in config and params as `null`

Now that Juju supports null configuration values the GUI needs to stop converting `null` values to "null". As a side effect all params for websocket rpc calls also send nulls for values which don't exist. This doesn't appear to have any negative side effects.

This is a fix for: https://bugs.launchpad.net/charms/+source/postgresql/+bug/1390858