fix issue 45
Merge pull request #46 from ywang19/FIX_ISSUE_45

Fix issue 45
fix issue 45 update
Merge pull request #47 from ywang19/FIX_ISSUE_45

fix issue 45 update
version 0.3.0.2
fix issue 18
Merge pull request #51 from ywang19/FIX_ISSUE_18

fix issue 18
fix issue 31 update
merge from upstream
sync up with upstream