KxSMB now compiling with last version of Samba, and sample project improvements

Hi @kolyvan,

I've made an update to your `Rakefile` in order to compile with the current version of Samba (4.0.7 instead of 4.0.6).

Also, I've modified the example project to make it able to test the library without touching any code. The first time I downloaded the library it was very confusing to set it up and start, so I though this changes will enable people to give it a try without getting so much into it.

I hope you like the changes.

Cheers,

Gonzalo.