Remove multiple-line comments

Original regex removed single-line comment blocks. Tested with
http://www.phpliveregex.com/ and in PHP v5.3.7.
multi-line comment blocks and ! escaping 

Removes multi-line comment blocks and allows for keeping comment block if first character is !
Minor touchup

The case of an empty comment wasn't matched. Now it is.
Merge pull request #2 from skeetergraphics/master

Remove multiple-line comments