perf(phpmin.js): Change in the single line comment regex
perf(phpmin.js): Change in the single line comment regex

Previous regex was not working in cases where there was a '#' or '//'
inside a string with single or double quotes.
All the credits of the new regex to @zx81 (from stackoverflow) for this
eye-opening contribution: http://stackoverflow.com/a/23667311/440898

swordf1zh/grunt-phpmin