server: remove use of memwatch

This plugin is outdated. Either use memwatch-next:
 https://www.npmjs.com/package/memwatch-next
Or heapdump. In this case, see:
 http://blog.yld.io/2015/08/10/debugging-memory-leaks-in-node-js-a-walkthrough/

Just remove the current implementation. It can still be added back
later.

package.json

@@ -35,7 +35,6 @@
     "winston": "~1.0.1"
   },
   "optionalDependencies": {
-    "memwatch": "~0.2.2",
     "mysql": "~2.8.0",
     "nodecastor": "~0.1.6",
     "pg": "~4.4.1",

server.js

@@ -7,8 +7,7 @@ var http     = require('http'),
     glob     = require('glob'),
     logger   = require('./lib/logger'),
     config   = require('./lib/config'),
-    chromecast = require('./lib/chromecast'),
-    monitor    = require('./lib/monitor');
+    chromecast = require('./lib/chromecast');
 
 var app = require('./lib/express'),
     server = http.createServer(app),
@@ -54,7 +53,6 @@ db
     if (config.get('chromecast:enabled')) {
       chromecast();
     }
-    monitor.start();
     server.listen(config.get('port'), function() {
       logger.info('Express server listening on port %d in %s mode',
                   config.get('port'),