Fix selectionString related Text issue

[fbo]

Text>>selectionString should look like this:

    selectionString: function() {
        var range = this.getSelectionRange();
        if (!range) { return ''; }
        var begin = (range[0] >  range[1]) ? range[1] : range[0];
            end   = (range[0] >= range[1]) ? range[0] : range[1];
        return  this.textString.substring(begin, end);
    },

Problem: When doing it this way instead of returning this.domSelection().toString() (undesirable), we have an editing problem.

When the cursor is moved BEYOND the end of a text using right key (say, cursor is at the beginning of a 3-character text and you press right key , the cursor is displayed at the end of that text, but once you type, characters are inserted before the last character in that text. At that point, this text instance is broken.

On a fresh text object, you can .. ... move the cursor to the end of the text using the mouse, ... move it EXACTLY to the end of the text using right arrow key without running into that issue.

Next thing I'm going to do is look into what happens onRightPressed etc.

[fbo]

The described behavior is reproducable in both Firefox and Chrome, which makes a fix likely to work in both browsers. Yippie.

[fbo]

What is still unclear: why does selectionString which should not alter the text's state influence text editing behavior?

[fbo]

Let's also have a look at what TextChunkOwner?>>fixChunks passes to Text>>setSelectionRange

[fbo]

fixed for FF and Chrome, but HTML only