fixed list.c
Fixed scheduler for work with lists
modifiche varie
problema malloc a livello sistema
Da risolvere il problema delle liste
Corretto problema in attivazione task e schedulazione round robin
Da risolvere il problema all'interno della terminate task
Alessandro finished
Merge branch 'master' of github.com:leonialessandro90/discovery_kernel

Conflicts:
	src/list.c
	src/list.h
	src/system_main.c
	src/user_main.c
Dummy rewritten
Reordered round robin scheduler's code and added the declaration of
list_round_shift to list.h
Reordered the activate_task function and solved the hidden bug of inserting a task into ready queue before a full context and stack initialization
system_main.h cleaned from useless/wrong function definitions, STACK type defined and used
Solved free() problem in terminate_task
Reordered files into a hierarchical fashion
Substituted dynamic memory allocation provided by std libs with personalized ones defined in memory.h
Now tasks are able to create new tasks! mem_alloc()'s maximum size has been adjusted to contain the stack of the tasks
Created FUN_TO_INT, added some comments in types.h, implemented a pretty simple (polling) wait() function and, in user_main.c, created nested tasks
Edited activate_task such that the stack uses the whole memory assigned by mem_alloc
implementata la FUN_TO_INT (non testata)
aggiunto al descrittore di processo un enumerate per discriminare se è stato bloccato in una int o in una funzione, ed è ok
Eliminato il campo TASK* next_task (sarebbe meglio fare i semafori con la lista normale).
messe due parentesi