Resolving build errors

Hello there!

Thanks for providing a golang RTP / RTCP library~ 
I'm excited to use it in a few side projects I've been meaning to start for some time.

Unfortunately, when attempting to build or import your library as documented in the Readme file, I would experience some errors that would prevent me using your library:

```
./transportUDP.go:46: too few values in struct initializer
./transportUDP.go:47: too few values in struct initializer
./transportUDP.go:128: too few values in struct initializer
./transportUDP.go:133: too few values in struct initializer
```

This pull requests introduces two commits:

  - One that formats the go code using the `go fmt` utility
  - Another that explicitly itemizes the fields when attempting to create a net.UDPAddr struct.