Remove Append and StringAppend
Cosmetic change
Remove reqNumToCreate constraint when creating request

It really degrades download speed.
Disable TCP_NODELAY for BitTorrent

To make Request messages more often packed into 1 packet.
Revert 53dde0a9

Reverted to the original strategy, but some values are tweaked.
Without TCP_NODELAY, 53dde0a9 does not work well.