Move the two CLI Usage into separate lines

Also, added the `or` word to clarify the two lines are not to be run sequentially.

README.md

@@ -476,6 +476,7 @@ Output will be sent to stdout if the `--output` flag is omitted.
 
 ### Usage
  `node-sass [options] <input> [output]`  
+ Or:  
  `cat <input> | node-sass > output`
 
 Example: