Eliminated unnecessary parameter from methods making concordances.
Fixed right context being one word too short.
Made how concordances are built from the forward indices
configurable.

By default, uses FI "word" for the text content of <w/> tags, "punct"
for the text content between <w/> tags and all other FIs as attributes
of the <w/> tags. Call Searcher.setForwardIndexConcordanceParameters()
to specify different FIs to use.