Fix bug in nonNegativeIntToBigEndian. Need to encode backwards starting from the end of the result buffer.
Fix bug in nonNegativeIntToBigEndian. Need to encode backwards starting from the end of the result buffer.

wentaoshang/NDN.JS,wentaoshang/NDN-on-Node,wentaoshang/NDN.JS,wentaoshang/NDN-on-Node