phrase search TS_phrase_execute code readability patch

Hackers,

The attached attempts to make comprehension of the code in
"TS_phrase_execute" a bit easier. I posted similar on the "typo patch"
thread of July 2nd/5th but my comments there reflected my mis-understanding
of the distance operator being exact as opposed to the expected
less-than-or-equal.

I had to make one assumption for the attached - that
"curitem->qoperator.distance" is always >= 0. In the presence of that
assumption the need for the OR goes away.

I don't follow why LposStart is needed so I removed it...

Not compiled or in any way tested...but its not major surgery either -
mostly code comments to make following the logic easier.

David J.