remove existing UI directory
add https://github.com/MiniProfiler/ui.git submodule
get profiler (minimally) working again with new UI code; still needs sql timings
small refactorings in the http handler
remove Timing.KeyValues - we've never used them on Stack Overflow and the UI has never shown them, either
massive refactoring to add CustomTimings and remove unneeded serialization from result json; sql server storage is currently commented out