Made sure Hits settings are copied when creating helper Hits objects.
Made -1 (for doc start/end) values work for forward index fetches.
Fixed off-by-one bug when highlighting part of document.
Made it possible to individually reverse HitProperty objects.

To reverse a HitProperty's comparison function, call .setReverse(true);
to sort on multiple HitProperty objects with some reversed and some not,
use HitPropertyMultiple and call .setReverse(true) on the component
HitProperty objects you want reversed.
Some tweaks to the experimental collocations functionality.

Collocations will allow you to find what words occur in the vicinity of
a set of hits.