Test refactor and enhancement

[sroysf]

Refactored and cleaned up tests, modified to make them more reliable when executing from within a Java environment (such as IDE).

Also simplified some test coverage redundancy.

[Hellblazer]

So, we really can't accept SF copyrighted stuff into here. We have an Apache license and even the test code has to be licensed as such.

[sroysf]

Added the on-demand reading capability of stdout / stderr tails to previous pull request. Also modified it so that you can specify the number of lines you want (up to the maximum of 4000 lines) to retrieve.

That said, from a PO perspective, I am forced to wonder if this is actually useful. Perhaps what the implementation should really be is the ability to grab a given window. Basically, implement the less command pgup/pgdn functionality. That way, instead of a somewhat random window of data, the end user could actually use this interface (via JMX or otherwise) to elegantly scroll through the log files. Food for thought?

[sroysf]

Also, buried in there is a subtle fix for an autoboxing problem that was leading to a very confusing NPE.