function SelectorPart(elementName, modifiers, text, line, col){
    
    SyntaxUnit.call(this, text, line, col, Parser.SELECTOR_PART_TYPE);

    /**
     * The tag name of the element to which this part
     * of the selector affects.
     * @type String
     * @property elementName
     */
    this.elementName = elementName;
    
    /**
     * The parts that come after the element name, such as class names, IDs,
     * pseudo classes/elements, etc.
     * @type Array
     * @property modifiers
     */
    this.modifiers = modifiers;

}
Represents a single part of a selector string, meaning a single set of
element name and modifiers. This does not include combinators such as
spaces, +, >, etc.
@namespace parserlib.css
@class SelectorPart
@extends parserlib.util.SyntaxUnit
@constructor
@param {String} elementName The element name in the selector or null
     if there is no element name.
@param {Array} modifiers Array of individual modifiers for the element.
     May be empty if there are none.
@param {String} text The text representation of the unit. 
@param {int} line The line of text on which the unit resides.
@param {int} col The column of text on which the unit resides.