adedd the ManamgedMemory class that implement Memcached slab memory model

Change-Id: I3274c469e30fbcea9a2c5e89188549960ca6c779
when _memoryLimit parameter has been set to 0, all memory needed by all slabs in alla slab class
is allocated in one only large memory block

Change-Id: I4a8ce9dbf268cfac99acf7f7ec6bde2104d0339a
refactoring for compilation problem

Change-Id: I5e7f4fef567e8289bafe43f94f1215102ae89932
refactoring for gcc warnign remove and creaiton of class FastCache
that embedd all memcached.

Change-Id: I4da2e632a337a3789bdd6f9b976c48336323565e
<< Memcached integration completed >>

All memcached code has been encapuslated into three class:
- ManagedMemory, implekemte slab memory managment
- FastHash, memcached hash implementation
- DataCache, set, get and remove memcached method implemented, This class use the upper described class.

Change-Id: Iefbf7142a5177749a8af4b476c63ad4d5a032ee1