Minor refactoring.
Fixed issues #84, #72

Issue #84: Test cases for InputFormats (for ARC)
Issue #72: Implement Hadoop bindings for webarchive-commons (for ARC)
Implemented ArcRecordWritable.
Both the Jwat and Wac versions of ExtractLinks gives the same exact output.
Minor refactoring, revised counters.
Switched ExtractSiteLinks and InvertAnchorText over to WacArcInputFormat; link structure the same, anchor text results better due to switch from ISO-8859-1 to UTF-8 decoding of pages.
WacArcInputFormat now generates ArcRecordWritables.
Merge branch 'working' into table-wrapper
Refactored WacMapReduceHBaseWrapperDemo, now takes advantage of TableChainMapper to reuse mapper for HDFS ARC data.