Eliminated SpansWithHit; added getHit() method to BLSpans.

Also added getHit(index) to SpansInBuckets. These methods are useful to
prevent re-instantiating Hit objects multiple times.
Added missing Javadoc tags
Removed call to get free memory from ForwardIndexImplV3.
Cleaned up nl.inl.util package and re-synched with our internal library.

- Inlined Utilities.getTerm()
- Created ArrayUtil class and moved compareArrays() methods there
- Moved Utilities.getPerWordCollator() to StringUtil
- Removed duplicate methods from Utilities
- Made some methods in DateUtil static
- Removed some deprecated methods
- Added some new methods from our internal library, to re-synch
Added more comments to HookableSaxHandler & related classes.
Fixed Javadoc for DocPropertyDecade and HitPropertyDocumentDecade.
Fixed sorting on document property when property is missing.

Made sure that, when comparing document properties, the empty string
(missing value) is sorted at the end instead of the beginning.
Added a way to get a larger snippet for a single hit.

Call Hits.getConcordance(Hit, int). N.B. Don't
use this method for retrieving normal concordances; for that,
instantiate a HitsWindow, call setContextSize(int) and call
getConcordance(Hit). That retrieves all concordances at once, which is
more efficient.
Made sure Doc & HitPropertyDecade also sort empty string at end.
Made Searcher.openForwardIndices() private.

No need to call this anymore since it's called automatically from
the Searcher constructor.
Some minor improvements to QueryTool.

- added snippetsize command
- added doc <id> to get metadata for document
- updated results display
- updated help
- removed openfi command (no need anymore)
Added methods to warm up the forward indices.

Warming up performs many reads, to get the index into the disk cache,
speeding up subsequent queries. Call Searcher.warmUpForwardIndices() to
do so. This may take a while.