[bug] Count the explode before the loop to avoid undefined index

[danyj]

There is small bug here https://github.com/intekhabrizvi/cssparser/blob/master/Cssparser.php#L50

that triggers undefined index 1 if there are 2 selectors without properties next to each other like

$CssParser->read_from_string('.something{}.something{}');

suggested fix

$level2 = explode(";",trim($level1[2][$i]));

if(count($level2) > 1){
	
	foreach($level2 as $l2)
	{
		if(!empty($l2))
		{
			$level3 = explode(":", trim($l2));
			
			
			if(isset($level3[1])){
				$this->css[$this->clean($level1[1][$i])][$this->clean($level3[0])] = $this->clean($level3[1]);
				unset($level3);
			}
		}
	}
	unset($l2);
}
unset($level2);

I know that if they are empty the should not be included in CSS but in some dynamic prints it happens.