Let key, cert as a file path

bin/remotedev.js

@@ -1,3 +1,15 @@
 #! /usr/bin/env node
+var fs = require('fs');
+var path = require('path');
 var argv = require('minimist')(process.argv.slice(2));
+
+function readFile(filePath) {
+  return fs.readFileSync(path.resolve(process.cwd(), filePath), 'utf-8');
+}
+
+if (argv.protocol === 'https') {
+  argv.key = argv.key ? readFile(argv.key) : null;
+  argv.cert = argv.cert ? readFile(argv.cert) : null;
+}
+
 require('./server')(argv);