Resolving build errors

[kellydunn]

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.

[Icedroid]

I have meet this error when I build GoRTP in go 1.1.2. Why don't resolve it?