Print a more user friendly error message on validation failure

overviewer.py

@@ -264,7 +264,12 @@ dir but you forgot to put quotes around the directory, since it contains spaces.
     # look at our settings.py file
     mw_parser = configParser.MultiWorldParser("settings.py")
     mw_parser.parse()
-    mw_parser.validate()
+    try:
+        mw_parser.validate()
+    except Exception:
+        logging.error("Please investigate these errors in settings.py then try running Overviewer again")
+        return 1
+
 
     # create our asset manager... ASSMAN
     assetMrg = assetmanager.AssetManager(destdir)

overviewer_core/configParser.py

@@ -289,7 +289,8 @@ class MultiWorldParser(object):
                         origs[key + "_orig"] = world[key]
                     world[key] = val
                 except Exception as e:
-                    print "Error validating %s: %r" % (key, e)
+                    logging.error("Error validating '%s' option in render definition for '%s':", key, worldname)
+                    logging.error(e)
                     raise e
             world['name'] = worldname
             world.update(origs)