fix bug of comparison with wrong types

raw_query['millis'] and self._slowms were both strings, they should be
ints for the comparison to be correct
Merge remote-tracking branch 'origin/master' into fix-slowms-type
use >=dargparse-0.2.2 which has argument value type support, value type
checking and conversion are done automatically now
Merge pull request #12 from xupeng/fix-wrong-comparison

fix bug of comparison with wrong types, thanks Xupeng!