Better errors

When I first created my account on local instance of OGV, I was unable to see the models loading. I checked here and there, looked into code but could not find why was it happening. Then later I came to know that somehow I deleted the obj folder from my user accounts folder and that was causing the problem. There was no error to show it so I was unable to find the problem first. This patch enables showing errors to this problem and various other errors that were missing. I have also added CSS classes to the existing errors so that they look like errors and not just a random string.