Fixed task filter option.
Added support for reporting task progress.
Updated readme with list of options.
Raised granularity of emitted progress event.
Fixed bug with TASK_DONE firing for all tasks when the first completes.
Added TASK_PROGRESS event.
addTask now returns the task id.
Refactored complete-, and progressTask methods.
Merge pull request #2 from vseventer/master

Reporting task progress