Fix for #266

Hello, 
This fixes(partially) #266, however, since there is no official resource for the holo_light version of ic_dialog_info, it isn't really possible to fix that here.

I tried uploading the existing resource to Android Asset Studio, but the end result is quite blurry even using the xxhdpi version of the resource. The only remaining option would seem to be using a different resource for the alerts.

I've also added the images(ic_dialog_alert_holo_light) to the appropriate drawable folders from Android SDK source, can be used as alternative if required.