More profiler cleanup:

More profiler cleanup:
* Move autoloader up a little bit so the profiler classes can use it
* Make Profiler into a singleton so it's lazy-constructed, $wgProfiler is now a configuration array (used 'visible' in ProfilerSimpleText as an example of other globals we can move into this array). If $wgProfiler is set to an object, it'll use that for back-compat
* Maintenance: rather than setting up the profiler and then disabling it, just disable it from the start
* Kill $wgProfiling -> now that ProfilerStub overrides profileIn() and profileOut(), it's not needed
* dumpHTML needs some fixes still