Finalize Sparkle class interface

[farbodahm]

After all of the readers and writers are finished, make sure main Sparkle class integrates with the provided readers and writers.

• Finalize Sparkle class (there are some todos)
• Add tests for Sparkle classs
• Add sample examples

[shahinism]

This interface should implement a contract based communication with Damavand based on DataChefHQ/damavand#20.