add the SpdyRadioAccessTechnology enum, which tracks the CTRadioAccessTechnology values.

it also adds 'unknown' and 'none'.
add some more logging to SPDY.m to make it easier to tell when new sessions are created
changes for SpdySession:

 - remove some hardcoded things
 - move ivars to the @implementation (.h => .m)
 - fix a GCD crash in releaseDispatchSources
 - add debugging to 'sort of' print out the spdy traffic on the wire (unencrypted)
update SpdyPersistentUrl to use the new CTTelephonyNetworkInfo radio access technology api in ios7 which
lets us know when we have moved from LTE to CDMA, etc.

If we are connected via WWAN, and get a radio access change from our previous state, then we send a ping
to make sure that the connection is still valid.

If it is not, we will then reconnect in short order, instead of waiting for the next 10 minute socket check.