Watcher Examples and Fixes

In response to @olegabr, I tried to make the watcher class a little more like QCacheProvider. This code creates a watcher that uses the QCacheProvider classes, adds an APC cache provider, and also adds an example page.

For the example page to work, the WATCH_CLASS configuration setting will need to be put in the config file. See the configuration.sample file for the right setting.