Corruption when retrieving long values #72

Great library. Thanks for writing it. Much better designed than the other options I looked at.

I found a data corruption bug when calling methods that return longs. The problem exists with both python 2.7 and 3.5. The code below will reproduce the problem. The bug is in the "d.getTime()" call. I've seen this problem with other calls to methods with a "long func()" signature.
https://gist.github.com/chipkent/555a33268044ce4cff19f379654d6965

When i run the reproducer code, I get:
Loading JPy 2.7
Fri Sep 02 14:05:11 MDT 2016
The following long should be >0
-327070828
Types: <type 'java.util.Date'> <type 'long'> <type 'long'>

Clearly the number of millis since the epoch should be positive.