add networking helper class
allow AlohaMac to to use addresses of Ethernet frames

- this allows to transparently use the SDR as a fake Ethernet device
- separate between broadcast and unicast transmission
add unified AlohaMac Tun/Tap radio example
Simplifying stack components so they use the default ports.
Merge pull request #8 from andrepuschmann/next_alohamac_fresh

AlohaMac changes for the next Iris release