Minor fixes

Fix an issue with unauthorized users causing a runtime panic.

First release

First official release.

Note:

• cgo releases use the libc DNS resolver to look up addresses on connect, but requires dynamic linking. nocgo builds are statically linked, and therefore have no dependencies, but at the cost of not using a libc resolver. This shouldn't cause any issues in general, but means that things like /etc/hosts might not be honoured, meaning that things like "localhost" aren't guaranteed to work. Using the raw IP or using a name from a name server should work fine.
• All builds are built with go1.5 on a linux/amd64 box. Darwin builds will be updated to proper OS X builds later.