rename SpdyPeristentUrl to SpdyPersistentRequest
add some more block typedefs to SPDY.h, so we can pass enums in a typesafe fashion:

typedef void (^SpdyNetworkStatusCallback)(SpdyNetworkStatus);
typedef void (^SpdyConnectStateCallback)(SpdyConnectState);
typedef void (^SpdyRadioAccessTechnologyCallback)(SpdyRadioAccessTechnology);
typedef void (^SpdyReachabilityCallback)(SCNetworkReachabilityFlags);

before, we were using SpdyIntCallback for all of them.
use the more explicit block typedefs in SpdyRequest.h and SpdyPersistentRequest.h
instead of SpdyIntCallback
make the SpdyConnectStateCallback take a SpdySession, as the connect states
from different sessions are overlapping and causing connect state confusion
add some debugging to SpdyBufferedCallback
add a weak SpdySession * session property to SpdyRequest.

keep a reference to our session in this property.
fix an ambiguity in SpdyPersistentRequest wrt/ the underlying stream's network status,
and our current reachability.
changes for SpdySession:

 - add a networkStatusCallback property
 - change the type of the connectionStateCallback to be more explicit
 - remove @synthesize, and related shadow ivars
 - fix a few problems with invalidateSocket where we were not releasing things properly
call the session's network status callback when creating it in SPDY.m