Merge pull request #14 from jbardin/master

Add an IdleTimeout to the Transport
Switch from net.Conn to *net.TCPConn

- Switch from an interface to a struct pointer in the rwTimeoutConn
  wrapper. In extreme cases, the interface overhead may be up to 5%
  (though it's probably very close to 0% at normal network speeds).
  Since http is only a TCP protocol, we don't need the net.Conn
  abstraction anyway.
Merge pull request #15 from jbardin/TCPConn

Switch from net.Conn to *net.TCPConn
feat: make it have the same public functions as "net/http".Transport

So it could be used as a replacement of "net/http".Transport now.
Merge pull request #16 from unihorn/19

feat: make it have the same public functions as "net/http".Transport
Fixes #17 add some docs re client re-use
Merge pull request #18 from tleyden/patch-1

Fixes #17 add some docs re client re-use