Draft support for person's with a social timeline and message posting activities.
Added draft wall feature. The user wall is constructed dynamically by aggregating all the messages from its followers. This approach is not very efficient as it requires dynamic merging of timelines as each view of the wall.
Updated the person using observer pattern for wall updates. This allows the Person entitiy to subscribe for updates from other Persons and removes the need dynamic generation of the wall. This design should should improve the efficiency of "wall" operation.
Added memory store for Person entity
Added scripts to build and run tasks
Added command parser for converting input strings to executable commands
Added Commnad line text input processor.