Poor handling of endPosition value of zero in editor.research()

[alankilborn]

Using PS 2.0, consider the following code:

# -*- coding: utf-8 -*-
from __future__ import print_function

from Npp import *
import re

matches = []
editor.research(r'.', lambda m: matches.append(m.span(0)), re.I, 0, 0)
print(len(matches))

I was surprised to see that the length of the matches list was non-zero when run on any file with content.

It seems the problem comes from running with endPosition equal to zero.
This apparently is used as a "special signal" to the receiving code that the effective endPosition should be the position of the last character in the document.

So of course I don't call editor.research in real code like I show above. That's just for illustration. My real code looked more like this:

 editor.research(r'.', lambda m: matches.append(m.span(0)), re.I, 0, editor.positionFromLine(editor.lineFromPosition(editor.getCurrentPos())))

and that will cause a failure when run with the caret on user line 1 of a file with content, because my intent is "no matches" in this case.

This is similar to the desire expressed by another user in #172, but that other user was nice as I'd call 172 a bug, just like I call this current issue a bug. :-)

As it is, I have to do extra error trapping to work around this issue.