3.0 remove cache set

This method has been a pain since its introduction. It causes a number  of negative things to happen:

* It leaks configuration information into all calling code. Making maintenance harder.
* It can easily cause nasty side-effects. Since Cache is a global facade, an unbalanced set() call can screw up cache writes elsewhere in the application.
* It is prone to error as developers have to remember to balance all the set() calls.
* It complicates the internals of Cache.

Instead of set developers can easily create multiple cache configurations for the various settings they need. This keeps both the calling code and CakePHP clean and simple.