npm and error messages

node_modules/csso/bin/csso

@@ -0,0 +1,16 @@
+#!/usr/bin/env node
+
+var cli = require('../lib/cli.js');
+
+try {
+    cli.run();
+} catch (e) {
+    // output user frendly message if cli error
+    if (cli.isCliError(e)) {
+        console.error(e.message || e);
+        process.exit(2);
+    }
+
+    // otherwise re-throw exception
+    throw e;
+}