Add log enable switch.
Merge remote-tracking branch 'upstream/master'
1. change anno.get() public; 2. anno.insert validate duplication.
Merge pull request #83 from topcircler/master

add log enable; change anno.get() public; validate duplication in anno.insert.
change duplicate anno error message.
Merge remote-tracking branch 'upstream/master'
Merge pull request #84 from topcircler/master

change anno duplicate error message.
Handle anno duplicate error
Merge pull request #85 from usersource/master

sync this branch with master