Updated the StatsInputStream.StatsCallback.bytesRead() interface method ...

...to take a long parameter instead of an int in order to support longer streams and be in line with the skip() method.

Updated the StatsInputStream.skip() method to also add to the total bytes read.
Added a test to support testing the mark(), skip(), and reset() methods in order to increase unit test branch coverage.
Migrate this test class of Junit 3 to Junit 4 please.