Upload built binaries from dev/master branches to Travis and Build Optimizations

This PR uploads built binaries to S3 after gzipping and tagging the filename with the Travis Build # and Commit.

It also no longer has travis building custom libmemcached, instead the package from ubuntu utopic is used for faster build-times. Go is no longer downloaded, instead the system go is used.

@jrconlin, @kitcambridge: r?
Considering that go 1.3 has been out for a bit, I think it's safe to use that as a minimum. Since we know that this works on 1.3 and have tested it accordingly, we're not going to frustrated folks using an unknown, older version.

I agree that we're not doing anything that strictly requires 1.3, but we're also being honest.