[Tilesathome] override config?

[Sebastian Spaeth]

> general.conf beeing a config which is in the SVN overriding everything is bad.
> There is sometimes the need to override something e.g. API servers for testing
> without breaking the autoupdate the client.
> 
> So there should be some last resort, not in svn, local config read
> from the client. Most of the time it should not exist though.

+1 from me. I sometimes need that for lowzoom render settings.

spaetz