AbbcExpandSelection function

Looks around a 'selected' [tag](...[/tag]) for (spaces and) NEW-LINES and
expands the selection to include them.

function AbbcExpandSelection (&$text, &$startpos, &$endpos, $length = -1);

Parameters:

text

(string)

startpos – in/out

(int)

endpos – in/out

(int)

length – optional, default: -1

(int) [optional]

Return value:

(int) difference between old and new selection length

Remarks:

Expansion stops before first non-space && non-new-line char or after first
new-line-char. For performance, strlen($text) can be given in $length, but
that's optional.

Implementation file: unb_lib/abbc.lib.php, line 1298