Quick stab at mentioning nginx/apache/vee config for SingularityUI dev.

Note, I haven't run Singularity since brunch stuff was brought in via Maven/Java, so I'm not sure if that changes thing (is there still a separate brunch process or is that combined into the Java server process now?).
Update .vee config and local dev suggestions (after actually running Singularity again locally to verify it works).
Merge pull request #238 from HubSpot/quick-little-proxy-doc

Quick stab at mentioning nginx/apache/vee config for SingularityUI dev.