update sources to Go v1.0

[laher]

I have made the rudimentary changes to make GoNetlink sources run in Go v1.0.

Notes:

• I added one extra folder-level in line with docs (src/netlink/*), in order to make it play nicely with 'go install'
• I also converted GITIGNORE to .gitignore and added 'pkg' folder. Apologies if this is undesirable.
• Note that although I have left the _Makefile_s in place, I haven't updated them, and I'm wondering if they're still needed. What do you think?

All the scripts in 'tools' folder have been tested in Linux (Mint 13) with Go v1.0 - all working OK.

I'm planning to use this library for anaylsing routing tables. Thanks very much for your good work. All the best.