Only use colors when stdout is a TTY

Author: Pepijn Verlaan

lib/log.js

@@ -20,7 +20,11 @@ module.exports = function(cfg) {
   }
 
   function color(s, c) {
-    return '\x1B[' + c + 'm' + s + '\x1B[0m'
+    if (process.stdout.isTTY) {
+      return '\x1B[' + c + 'm' + s + '\x1B[0m'
+    } else {
+      return s;
+    }
   }
 
   log.info = function() {