Added javascript code to pass the information of the `window.performance.timing`
object to requestlog 500ms after the load event is fired.
Added option in `adhocracy.ini` to activate this monitor
`adhocracy.monitor_page_performance`
Activated the new code with the option in the hhu.cfg
And the changes here reflect the changes in upstream adhocracy.
Changed the timeout after that the navigation timing info is send to 10ms.
Changed the onLoad object from document to window, on some browsers the
load event is only on window object fired.
Simplified the ajax send request for the navigation timing.
Merge branch 'record-timings' into feature-monitor-pager-clicks
Port liqd/adhocracy#401. Fixes #119.
Merge branch 'feature-monitor-pager-clicks'