Make __repr__ slightly more detailed and add a few missing ones.

This includes raw events (which didn't have any) and a few other
types that were missing them. Upon review some more useful fields were
added to the repr output which would be more useful during debugging.

discord/audit_logs.py

@@ -93,7 +93,8 @@ class AuditLogDiff:
         return iter(self.__dict__.items())
 
     def __repr__(self):
-        return '<AuditLogDiff attrs={0!r}>'.format(tuple(self.__dict__))
+        values = ' '.join('%s=%r' % item for item in self.__dict__.items())
+        return '<AuditLogDiff %s>' % values
 
 class AuditLogChanges:
     TRANSFORMERS = {
@@ -164,6 +165,9 @@ class AuditLogChanges:
             self.after.color = self.after.colour
             self.before.color = self.before.colour
 
+    def __repr__(self):
+        return '<AuditLogChanges before=%r after=%r>' % (self.before, self.after)
+
     def _handle_role(self, first, second, entry, elem):
         if not hasattr(first, 'roles'):
             setattr(first, 'roles', [])