1. Removed shm mapping bug. run-servers.sh sleeps for a while b/w server
starts.

2. Clients round robin b/w servers. This fixes the issue where a server
stalls because its pipeline is not full and clients wait on that server.

3. Introduced a new parameter: WS_SERVER. This is the number of outstanding
responses that one server process can have. This should not be as large as
S_DEPTH when we use a large number of server processes.

4. Performance: 16 million echoes with 4 random reads.