Adds better --only option handling.
Adds better --only option handling.

shinnn/css-minification-benchmark,tavriaforever/css-minification-benchmark,shinnn/css-minification-benchmark,webdev1001/css-minification-benchmark,GoalSmashers/css-minification-benchmark,tavriaforever/css-minification-benchmark,denji/css-minification-benchmark,denji/css-minification-benchmark,webdev1001/css-minification-benchmark