Kick Ass Cache APC: Capture the page output and cache it using APC

This class can capture the page output and cache it using APC.

It computes a cache key for the current request based on the page URI and the request parameters.

If the cached page with the computed key already exists, the class serves the cached content and exists.

If the cached page does not exist yet, the class tries to lock the access to the cache key. If successful, the class captures the page output, stores the captured output, and unlocks the cache.