added: to Big<> class: support for NaN flag (Not a Number)

bool Big::IsNan() - returns true if the NaN flag is set
       void Big::SetNan() - sets the NaN flag
       The NaN flag is set by default after creating an object:
         Big<1, 2> a;    // NaN is set (it means the object has not a valid number)
         std::cout << a; // cout gives "NaN"
         a = 123;        // now NaN is not set
         std::cout << a; // cout gives "123"
       The NaN is set if there was a carry during calculations
         a.Mul(very_big_value); // a will have a NaN set
	   The NaN is set if an argument is NaN too
	     b.SetNan();
	     a.Add(b);  // a will have NaN because b has NaN too
       If you try to do something on a NaN object, the result is a NaN too
         a.SetNan();
         a.Add(2);  // a is still a NaN 
       The NaN is set if you use incorrect arguments
         a.Ln(-10); // a will have the NaN flag
       The only way to clear the NaN flag is to assign a correct value or other correct object
         supposing 'a' has NaN flag, to remove the flag you can either:
         a = 10;
         a.FromInt(30);
         a.SetOne(); 
         a.FromBig(other_object_without_nan);
         etc.
changed: renamed macro CONSTANTSGENERATOR to TTMATH_CONSTANTSGENERATOR



git-svn-id: svn://ttmath.org/publicrep/ttmath/trunk@152 e52654a7-88a9-db11-a3e9-0013d4bc506e

constgen/Makefile

@@ -1,6 +1,6 @@
 o      = main.o
 CC     = g++
-CFLAGS = -s -O2 -DCONSTANTSGENERATOR
+CFLAGS = -s -O2 -DTTMATH_CONSTANTSGENERATOR
 name   = gen
 
 

constgen/main.cpp

@@ -91,7 +91,7 @@ void CalcE()
 	ttmath::Big<1,400> e;
 	ttmath::uint steps;
 
-	// macro CONSTANTSGENERATOR has to be defined	
+	// macro TTMATH_CONSTANTSGENERATOR has to be defined	
 	e.ExpSurrounding0(1, &steps);
 	std::cout << "---------------- e ----------------" << std::endl;
 	e.mantissa.PrintTable(std::cout);
@@ -105,7 +105,7 @@ void CalcLn(int x)
 	ttmath::Big<1,400> ln;
 	ttmath::uint steps;
 
-	// macro CONSTANTSGENERATOR has to be defined	
+	// macro TTMATH_CONSTANTSGENERATOR has to be defined	
 	ln.LnSurrounding1(x, &steps);
 	std::cout << "---------------- ln(" << x << ") ----------------" << std::endl;
 	ln.mantissa.PrintTable(std::cout);