Implemented handleClaimChunkAdd

Also:
- Commented out implementation of handleClaimChunkRemove, got to
re-write along the lines of handleClaimChunkAdd.
- Added ChunkNotInClaimException, NoclaimWithMatchingIdException, and
NoClaimWithMatchingNameException.
- Added addChunkToClaim and removeChunkFromClaim methods to
ClaimRegistry. Implemented the addChunkToClaim methods.