trunk-tracking: port r3937 which supports custom url-valued attributes overriding spec-defined ones
Merge branch 'trunk-tracking' of github.com:pagespeed/ngx_pagespeed into trunk-tracking
port r3964 which handles options in request cookies
port 3967 which adds a fetch_until to the prioritize critical css test
port r3966 by turning off CompressMetadataCache which breaks ipro
Merge pull request #677 from pagespeed/jefftk-update-trunk-tracking

trunk-tracking: update from r3949 to r3967
port r3968 which is supposed to be just a test that a bug isn't present, but in ngx_pagespeed actually triggers that bug.  This needs to be fixed, but is out of scope for a trunk-tracking update.
trunk-tracking: also turn off ProactiveResourceFreshening until we fix PSOL.
Merge pull request #678 from pagespeed/jefftk-update-trunk-tracking

port r3968 which is supposed to be just a test that a bug isn't present...
clean up the conf file overrides to turn off proactive resource
fetching and compressed cache.  the compressed cache was ok but
proactive resource fetching consistently fails system tests in nginx
Merge pull request #680 from pagespeed/jmarantz-clean-proactive

clean up the conf file overrides to turn off proactive resource
dependencies: include psol as a dependency
Merge pull request #681 from pagespeed/jefftk-psol-dep

dependencies: include psol as a dependency
readme: use nginx 1.6.0
Merge branch 'master' into trunk-tracking
add ngx test support for RequestOptionOverride option
Merge pull request #684 from pagespeed/crowell-requst-option-override

add ngx test support for RequestOptionOverride option
Rename QueryParams::Parse to ParseFromUrl. Add a wrapper that takes an untrusted string.
Merge pull request #688 from pagespeed/matterbury-queryparams

Rename QueryParams::Parse to ParseFromUrl. Add a wrapper that takes an untrusted string.
Added query parameter to make the other query parameters 'sticky' by returning cookies that set them so are passed in subsequent requests.