refactor: migrate misc files to ES2015

lib/constants.js

@@ -1,7 +1,9 @@
-var fs = require('graceful-fs')
-var path = require('path')
+'use strict'
 
-var pkg = JSON.parse(fs.readFileSync(path.join(__dirname, '/../package.json')).toString())
+const fs = require('graceful-fs')
+const path = require('path')
+
+const pkg = JSON.parse(fs.readFileSync(path.join(__dirname, '/../package.json')).toString())
 
 exports.VERSION = pkg.version
 

lib/detached.js

@@ -1,9 +1,11 @@
-var fs = require('fs')
+'use strict'
 
-var Server = require('./server')
-var configurationFile = process.argv[2]
-var fileContents = fs.readFileSync(configurationFile, 'utf-8')
+const fs = require('fs')
+
+const Server = require('./server')
+const configurationFile = process.argv[2]
+const fileContents = fs.readFileSync(configurationFile, 'utf-8')
 fs.unlink(configurationFile, function () {})
-var data = JSON.parse(fileContents)
-var server = new Server(data)
+const data = JSON.parse(fileContents)
+const server = new Server(data)
 server.start(data)