Code Refactoring

Major change in this commit:
1. Move all the classification mess from lexicalAnalysis.c to tokenClassification.c.
2. Replace the ambiguous name "Token" by "Opr".
3. All the local pointer variables ( such as Symbols_table ), are seperated into relevent functions and are
declared as static local variable, in hope that their value can be used by the next function call.
4. The project is still uncompiled. ( which might be a real spook! )

I'm just wondering the best way to include file.
Say in some file "file1.c" I need function "Foo" implemented in "file2.c".

Senario 1:

	"file1.c"

	#include "file1.h"
	#include "file2.h"
	foo();

-------------------------

Senario 2:

	"file1.c"

	#include "file1.h"
	foo();

	"file1.h"

	#include "file2.h"

------------------------

What's the best way?