Updated readme
Bug fixes

* use dirname(__FILE__) instead of WP_PLUGIN_DIR for easier merges;
* fix options file name in the error messages;
* remove error and message parameters from $_POST['_wp_http_referer'];
Use paths relative to dirname(__FILE__)
Merge branch 'master' into wordpress.org

Conflicts:
	core.php
	lib/PageHandlers.php
	pages/ApcCache.php
	pages/FileCache.php
	pages/Memcache.php
	pages/Memcached.php
	pages/ZendDiskCache.php
	pages/ZendShmCache.php
	pages/eAcceleratorCache.php
	pages/options-object-cache.php
	pages/xCache.php
	readme.txt