Extend alpha_find_stylesheet() with less

In D6 has a limitation of less.module. It is only works with *.css.less files, but in D7 this limitation is solved.
I think this 'css.less' can be replaced with 'less'
in this line:
foreach (array('css', 'css.less', 'sass', 'scss') as $extension) {
in alpha_find_stylesheet() function.