* Limit the amount of inbound RPC connections.
* Increment/decrement the right variable.
* Implement TestRPCMaxInboundConnections.
* Make go vet happy.
* Increase RPCMaxInboundConnections to 128.
* Set NUM_CLIENTS=128 in the rpc-idle-clients stability test.
* Explain why the P2P server has unlimited inbound connections.