Added simple memory allocator - 2013.07.30.

Added simple memory allocator.
- but functions are not implemented.
Implemented simple memory allocator - 2013. 07. 31.

Implemented simple memory allocator
    - but not tested yet
Fixed errors - 2013.08.03.

Fixed errors.
Tested basic funtion of simple memory allocator.
Fixed bug and Added GetMaximumAvailableMemorySize() - 2013.08.04.

Fixed bug on simple memory allocator.
Implemented Simple_GetMaximumAvailableMemorySize().