Connection pooling for thread-safe communication with glock server

I have kept the API for this client the same for the end user.

The main change is that we now have to specify the size of the
connection pool at new client

The inner working is such that each operation with grab one connection
from the channel. If the connection is bad, that will be redialed and
replace with a new connection.
connection struct that wraps around conn and reader for thread-safety

Move functions - readResponse, fprintf, redial to have a connection
pointer receiver; This way each client operation(lock, unlock) has an independent connection
Minor formatting fix
Merge pull request #4 from iron-io/feature-connection-pool

Connection pooling for thread-safe communication with glock server