Added WARC support to analysis:

WARC counterparts created for Count*.java
WARC support added to ExtractUniqueUrls (can handle mix of WARC and ARC files)
FindUrls -> FindArcUrls and FindWarcUrls

To use MultipleInputs (i.e. to handle WARC and ARC in single class) would have
required restructuring of Count* code. FindUrls does not implement MultipleInputs
either, because this makes obtaining input filename impossible without hacky code
(see JIRA ticket MAPREDUCE-1743 and
http://stackoverflow.com/questions/11130145/hadoop-multipleinputs-fails-with-classcastexception).