Added an example for a multi-protocol app using strongly typed data and protobufs

[avive]

Here's a little examples that shows how to build a node with multiple app protocols using protobufs as the wire format. The example creates a node that implements two protocols - ping and echo and the example demonstrate exchanging methods using the two protocols between two peers.

[whyrusleeping]

log.Fatal will halt the program immediately, we would never get to return false

[avive]

good catch - got rid of all log.Fatal in latest check-in

[hsanjuan]

I had a rather quick look. I don't see anything wrong or hard to follow. Seems a good example to me, very illustrative!

There are a couple of commented lines and todos which we might want to clean-up, but they don't bother me much.

Thanks!

[avive]

I'd like to do some cleanups before this can be merged. I will commit here when I think this is 100% ready for merging. For example, unrolling GX imports to their canonical names. ok?

[avive]

I can't really get the example to go build when replacing the GX deps with the canonical github repo names. Can one of you guys help me out with that? I assume we don't want code checkins with GX deps correct?

[hsanjuan]

If you use the canonical github repo, and run gx-go rewrite on the base of this repo, and then try to build it (with the gx-rewritten paths), does it work? In that case, just add that step to the instructions... otherwise you may need to add your own package.json to the example folder...

[avive]

I'm still having trouble with GX and deps :-(

[Stebalien]

@avive I believe your problem is the github.com/avive/go-libp2p/... import (two different paths to import the same package). Would you mind if I pushed a version with gx fixes to your branch (gx can be a bit tricky, probably easier to learn by example)?

[Stebalien]

So... Apparently, force-pushing master to a PR will close it. Worse, because this PR was made master to master, it appears that I can't reopen it. New PR: #280.