New Plugin API

- Homebridge calls single exported initializer function and passes an
API object
  - No more require() for HAP classes (doesn't play well with plugin
structure)

lib/plugin.js

@@ -18,12 +18,7 @@ module.exports = {
 
 function Plugin(pluginPath) {
   this.pluginPath = pluginPath; // like "/usr/local/lib/node_modules/plugin-lockitron"
-  
-  // these are exports pulled from the loaded plugin module
-  this.accessory = null; // single exposed accessory
-  this.platform = null; // single exposed platform
-  this.accessories = []; // array of exposed accessories
-  this.platforms = []; // array of exposed platforms
+  this.initializer; // exported function from the plugin that initializes it
 }
 
 Plugin.prototype.name = function() {
@@ -58,12 +53,8 @@ Plugin.prototype.load = function(options) {
 
   var mainPath = path.join(this.pluginPath, main);
   
-  // try to require() it
-  var pluginModule = require(mainPath);
-  
-  // extract all exposed accessories and platforms
-  this.accessories = pluginModule.accessories || {};
-  this.platforms = pluginModule.platforms || {};
+  // try to require() it and grab the exported initialization hook
+  this.initializer = require(mainPath);
 }
 
 Plugin.loadPackageJSON = function(pluginPath) {
@@ -141,8 +132,12 @@ Plugin.installed = function() {
     // just because this path is in require.main.paths doesn't mean it necessarily exists!
     if (!fs.existsSync(requirePath))
       continue;
-    
-    var names = fs.readdirSync(requirePath);
+
+      var names = fs.readdirSync(requirePath);
+
+    // does this path point inside a single plugin and not a directory containing plugins?
+    if (fs.existsSync(path.join(requirePath, "package.json")))
+      names = [""];
     
     // read through each directory in this node_modules folder
     for (var index2 in names) {