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?
So no more symlinking Go into `bin/go`?