* fix permission overflow from return results
also:
* hide private methods and fields for reflection that require permissions
* delete stale index of task directly
add HugeGraph.java and TaskScheduler.java: separate commits to avoid no git diff
implement: #209
Change-Id: Iccfbd47c213e1e13122190d1242778031e8a957c
* Increase task result limit
* Let task input and result property datatype as blob
* Support config task input and result size limit
Change-Id: Ib2c4bdf25e4604d8bea47802e724c0f0934170fb