Sync
Sync

- Parses incoming sync message task payload and synch key from client.
- Accomodates all four combinations of present/absent key and taks payload.
- Loads user data on server side.
- Finds common ancestor between incoming synch key and stored user data.
- Extracts the data subsequent to the common ancestor -> subset.
- Generates a new client synch key.
- Refactored the above into helper methods.

whitel/task-server,whitel/task-server,goldenHairDafo/taskd,whitel/task-server,goldenHairDafo/taskd,goldenHairDafo/taskd,goldenHairDafo/taskd,whitel/task-server,goldenHairDafo/taskd,whitel/task-server