readme: google pagespeed docs now include ngx_pagespeed
keepalive-test: Test that we handle keep-alive requests OK

Add a keepalive test which is repeated 100 times, with us both
behind the gzip filter and directly behind nginx's output filter.
The reason for that is that modules running after us can mask
our errors, this at least tests the most used ones.

This CL adds a failure to the expected failures, as currently,
this tests gives suspicious messages in nginx's error.log:
"client prematurely closed connection while sending response to client"

We should probably also test other code paths, like .pagespeed.
resources and the beacon with post requests as well. If this approach
is generally ok, I can proceed to add those as well.
Merge pull request #389 from pagespeed/oschaaf-keepalive-test

keepalive-test: Test that we handle keep-alive requests OK
keepalive-tests: add more keepalive tests

- beacon get requests
- beacon post requests
- requests on /ngx_pagespeed_static
- requests on .pagespeed. resources
Merge pull request #391 from pagespeed/oschaaf-keepalive-test-more

keepalive-tests: add more keepalive tests
ngx-list-iterator: Make it easier to iterate over headers.  Fixes #359.
Merge pull request #393 from pagespeed/jefftk-loop-headers

ngx-list-iterator: Make it easier to iterate over headers.  Fixes #359.
Merge branch 'master' into trunk-tracking