Added $tmpCache

* phpFastCache::$useTmpCache = true; // faster checking cache for LOOP
Only. If you don't use LOOP, don't spend more memory.
* Example:
* WHILE() {
*   $cache = phpFastCache::get("name");
* }
* LOOP() {
*   $cache = phpFastCache::get("name");
* }
*    --> THE NAME maybe duplicated some times, if you set $useTmpCache
it will check from $Tmp first before IT connect to Cache Memory or Open
Files to check.
*        Will be faster a little bit if you know what you are doing.