Complexity of the design regarding path types

[juagargi]

There exists a number of slayers paths that are necessary to express the different types of paths that the implementation supports.

We also have the snet.DataplanePath interface that is needed to synchronize values between the SCION header and the particular path header.

We also have the snet.RawPath that has the unprocessed path received in the packet. Why though?

We also have the snet.RawReplyPath, because RawPath cannot be reversed?

We should get rid of all but the slayers ones, and if we want to hide the particularities of the types behind a facade, a type that just delegates the needed functionality to the underlying slayers path.