Fix wording as recommended by Chris. Added additional documentation about indexes.
Fix wording as recommended by Chris.
Added additional documentation about indexes.

braydonf/bitcore-node,snogcel/bitcore-node-dash,kleetus/bitcore-node,braydonf/bitcore-node,zcoinrocks/bitcore-node,kleetus/bitcore-node,zcoinrocks/bitcore-node,snogcel/bitcore-node-dash