Implemented the PoolCounter feature and did some general refactoring in the areas...

Implemented the PoolCounter feature and did some general refactoring in the areas that it touched.

* Renamed Article::outputFromWikitext() to Article::getOutputFromWikitext()
* Factored out cascade protection updates
* Removed recently-added Article::tryParserCache(): misnamed, can be done in one line of code in the caller. Deprecated OutputPage::tryParserCache().
* Made some functions public instead of protected when they could be useful from hooks.
* In ParserCache, removed PHP 4-style ampersands

In Article::view():
* Factored out robot policy logic, "redirected from" header, patrol footer, diff page, revdelete header, CSS/JS formatting, footer, namespace header, missing article error
* Removed some variables, renamed some others, fixed incorrect use of empty()
* Used the refactored footer section to do a couple of early returns and unindent a massive if(!$outputDone) block
* Removed fantasy interpretation of $this->getContent()===false in comment
* Don't try the parser cache when ArticleViewHeader specified $outputDone=true
* Move timing hack to getOutputFromWikitext()
* Stop using $wgOut->parserOptions() with save/restore nonsense every time you want to change something in it. This is meant to be OOP.
* Don't overwrite the article text with an error message and then pretend to write it to the cache, that's confusing