GitLab

Uses shared external package peer task queue in place of peer request queue. Shared by graphsync.

Add comments to all exported functions, extract the utils for creating instances in testnet.go,
moves integration tests to bitswap_test

BREAKING CHANGE: removed one constant -- rebroadcastDelay -- which I believe was unused

* HasBlockBufferSize and provideKeysBufferSize no longer matter as we have an
  infinite in-memory buffer.
* provideWorkersMax now defaults to 6 so changing this to 16 actually _increases
  memory consumption.

In preparation for switching over to go modules entirely. We no longer need our
fork.

License: MIT
Signed-off-by: Jakub Sztandera <kubuxu@protonmail.ch>