Socket::address: use existing len() method.
Socket::address: add constructors from standard addr types

Also make insert and remove parameters constants.
Socket::address: add withPort()
Socket::address: add print() method
Socket::address: add unit tests for print()
Socket::address: fix constructor documentation
Socket::address::print(): minor fixes
Merge pull request #14 from aberaud/master

Socket::address: add usefull methods