Replace before-plugin-install hook to afte-plugin-install, fix istallation issue on Mac (#361)

.gitignore

@@ -1,3 +1,4 @@
+.DS_Store
 #ignore the files built by npm install
 node_modules/*
 

plugin.xml

@@ -6,7 +6,7 @@
         <keywords>cordova,code,push</keywords>
         <repo>https://github.com/Microsoft/cordova-plugin-code-push.git</repo>
 
-        <hook type="before_plugin_install" src="hooks/beforeInstall.js" />    
+        <hook type="after_plugin_install" src="hooks/afterPluginInstall.js" />    
         <dependency id="code-push" version="2.0.4" />
         <dependency id="cordova-plugin-dialogs" version=">=1.1.1" />
         <dependency id="cordova-plugin-device" version=">=1.1.0" />