Naming & modularization

[daviddias]

To avoid future confusion such as -- #67 (comment) --. I want to propose that we adopt the following:

• go-pubsub - The pubsub API and the thing that knows how to take multiple pubsub implementation
• go-floodsub - The floodsub implementation
• go-gossipsub - The gossipsub implementation

This will make it very clear that libp2p/IPFS support multiple pubsub implementations and that we encourage everyone to try new ones.

[Stebalien]

My current plan is to:

1. Remove the current go-libp2p-pubsub.
2. Rename this package to go-libp2p-pubsub.
3. Eventually extract the floodsub/gossiphub from it.

The implementations are currently bundled with this repo as we'll probably need to refactor things quite a bit to get the interfaces right.

[hsanjuan]

We can proceed with this at this point?

[vyzo]

We can probably proceed with steb's 1&2.

[daviddias]

This is now solved.