[TASK] Integrate CreationInterface
[TASK] Integrate EntityService and make use of it
[TASK] Streamline property manager configuration for meetings
[TASK] Integrate validation and exception handling feedback for JSON context
[TASK] Force persistence state on new entities
[TASK] Force JSON date format on saving data to server

Date.toJSON usually contains microseconds, hence W3C date format is used at the server.
Besides that, different client vendors vary in using the microsecond part - thus, this is an explicit conversion.
[DEBUG] Disable HTTP heartbeat for debugging reasons
[WIP][TASK] Preliminary data storage API with HttpInterceptor interaction

The previous approach using low-level $http seems to be to complicated. Using the higher-level $resource object seems to be better and allows better scoping (meeting, task, ...) and object coupling.