Feature request - filter command to support a list of mac addresses for BPF filtering

[mpihelgas]

Currently the YAML file containing BPF filters seems to support only network addresses (i.e., net BPF filter).
In some situations it would be nice to be able to also add MAC addresses to be filtered (i.e., ether host BPF filter).

Thanks!

[markuskont]

Done in fbe41df

[mpihelgas]

Thank you, I'll run some tests to provide more feedback.

First thing I noticed, there seems to be some leftover noisy debug printing on https://github.com/StamusNetworks/gophercap/blob/master/pkg/filter/condition.go#L214