GCC 4.9 Signed/Unsigned Compare Fix

Tweaked the unit tests so that GCC 4.9 no longer emits warnings about signed-to-unsigned integer comparisons.

This is not a fault of the code per se, but is rather a fault of the manner in which Catch parses/implements assertions.
eofbit Fix

Fixed a bug in the String stream extractor which was causing eofbit to be spuriously set when a line which occurred at the end of the stream was extracted.  eofbit should not be set until an attempt is made to extract a line and the stream is already empty.