Update IndefiniteArticle.class.php

Added conditionals to recognize numbers that start with 8, 11 and 18 AND are pronounced "eight", "eighty", "eighteen", or "eleven" (i.e. 18,000 or 11,000) and NOT ones that are usually pronounced with "one" (i.e. 180 or 1,100,000)
Update IndefiniteArticle.class.php
Update IndefiniteArticle.class.php
Merge pull request #1 from kjbjm/patch-1

Patch 1 adding support for strings starting with a number. Thanks kjbjm!