Allow to specify trimString count number

[JoniJnm]

Hi,

I use behat in verbose mode (-vvv). When there is an exception behat calls ExceptactionException::__toString, and this function uses ExceptactionException::trimString with the default $count value.

The function looks like:

Mink/src/Exception/ExpectationException.php

Lines 151 to 160 in 916471d

	protected function trimString($string, $count = 1000)
	{
	$string = trim($string);
	if ($count < mb_strlen($string)) {
	return mb_substr($string, 0, $count - 3).'...';
	}
	return $string;
	}

I would like to disable the $count or increase the value. Maybe adding a ENV variable could be useful?

I can not see the full stack trace with only 1000 chars