split cli and helper, add bin entry to package.json

cli.js

@@ -0,0 +1,32 @@
+#!/usr/bin/env node
+'use strict';
+
+const argv = require('minimist')(process.argv.slice(2));
+const swm = require('./swm.js');
+
+if (argv.help || argv.h) {
+    console.log(
+`Simple helper for turning on/off connected/disconnected monitors with 'xrandr'.
+
+Usage:
+
+'swm [monitor-1...montior-n]' e.g. 'swm LVDS1 HDMI1'
+
+If 'monitor-1' to 'monitor-n' is specified 'swm' will turn on these monitors
+and place them from left to right in the order given. If a provided monitor is
+not connected it will be skipped.
+
+If no monitors are specified all connected monitors will be turned on and
+placed from left to right in alphabetical order of their name.`
+    );
+
+    process.exit(2);
+}
+
+swm.getDevices()
+    .then(swm.generateXrandrOptions.bind(null, argv._))
+    .then(swm.switchDevices)
+    .then(swm.executePostCmd.bind(null, argv.postCmd))
+    .catch(err => {
+        console.error(err);
+    });