Code to handle redirect limits in the async API.
portably handle prohibited headers across SPDY variants.
Merge pull request #409 from square/jwilson_0105_redirect_tests

Code to handle redirect limits in the async API.
test case for syncRequest
Merge pull request #410 from adriancole/spdy-prohibited-headers

portably handle prohibited headers across SPDY variants.
Merge pull request #403 from lingmingyb/syncRequest

test case for syncRequest