Correct REST documentation.

The doc misleadingly says that the third value of the task-status-array contains the "# of tiles remaining", although the "expected remaining time in seconds" is contained in that value.
Correct javadoc.

The third parameter of the task-status-array contains the expected remaining time and not the # of remaining tiles.
Merge pull request #241 from buehner/doc-correction

Doc correction regarding job status array