Neutu can generate excessively long fetches

[pgunn]

Sometimes neutu will perform fetches of seg data that involve excessively long URLs. This doesn't create problems (as far as I know) if neutu is talking directly to a DVID, but it can make having a webproxy in front of DVID require very unusual configuration to allow for the very large request urls, and I'd worry that even without a web proxy the urls might eventually go over what's allowed by the http spec (just speculation).

I suggest, when doing requests that would generate very long urls, instead splitting those requests into several http conversations.