Parallel block download(Updated)

[rairyx]

Implemented parallel block download. WIP

[janx]

I tried to run this branch but got this error:

Collecting miniupnp (from -r requirements.txt (line 20))
  Could not find a version that satisfies the requirement miniupnp (from -r requirements.txt (line 20)) (from versions: )
No matching distribution found for miniupnp (from -r requirements.txt (line 20))

It looks like the PR depends on an old pyethereum release? What's the pyethereum/pydevp2p version do you use?

[rairyx]

Sorry the PR is built on pyethereum 1.60 and pydevp2p 0.92. I'm updating it to the newest version of pyethereum

[rairyx]

Updated to the latest version of pythereum and pydevp2p