OZP-282: Perform code review
> OZP-61: Migrate RPC API.

1. Added js doc comments to RPC code.
2. Removed global JSON and gadgets variables.
3. Moved getOpenedWidgets logic from DashboardContainer to DashboardInstance.
4. Fixed getOpenedWidgets to include background and floating widgets.
5. Removed the reference to OWF's jQuery object by the sample widgets and imported jquery separately for them to use.
6. Added code to Color Client and Color Server to test RPC direct messages in addition to RegisterFunctions.