Source code refactoring

Move several files in order to improve the tree organization.
Moreover, includes cmake scripts for "cc", "as" and "ar".
Remove cmake files and add a python script to generate the Makefiles

I decided to use Makefiles because the cmake do not support
multiples compilers for the same language.
Create a main Makefile and apply minor "bug" fixes

Improve the "prepare.py" script to compile the build tools,
the kernel and the system library.
Improve the script for Makefile generation and add support to compile the 'libc'
Improve 'prepare.py' script to generate smaller makefiles

The XXXX_OBJ_FILES target were improved to use the 'patsubst'
command from 'make'. Thus, we can replace the list of object
files by only one command.
Fix a error message of AR tool
Add compilation targets for bootloaders
Add support to compile the bootloaders

Additionaly, include a minor fix to load the kernel
syscall library (kernel32.so).
Move some machine dependent functions to x86 architecture directory