mapserver tilecache and proxies

If you end up doing a lot of work on mapserver and tilecache behind corporate proxy servers, you’re likely to hit a couple of snags, when the proxy thinks you’re trying to do something evil, when really all you want to do is seed a tilecache or look at an external WMS server. Fortunately there are a couple of useful workarounds, which I record here for my own sanity as much as anything else!