minor enhancements

Added apache mod_deflate, mod_expires, mod_headers
Added PECL Memcached module with SASL support
Use GZIP -9 compression for tarball
Set ServerSignature, ServerTokens, and HostnameLookups to appropriate values
Added built-in PEAR in include_path
Set apc.stat = 0 since files can't change between service restarts
Added user definable hook scripts that are executed right before apache service starts
Added WWWROOT config variable support so document root doesn't have to be the top directory
PHP uses mysqlnd instead of libmysqlclient

The compiled slug is about 14MB, which is larger than HEAD, but is to be expected with the extra libraries needed. Can probably reduce the slug size another 1MB or so by removing the libmysqlclient.so.16 since it is replaced by mysqlnd.