test: make namespace usage less intrusive in math examples.

test/math/pi.cpp

@@ -20,8 +20,10 @@
 
 #include "core.h"
 
-using namespace lol;
-using namespace std;
+using std::printf;
+using std::sqrt;
+
+using lol::real;
 
 int main(int argc, char **argv)
 {

test/math/remez-matrix.h

@@ -80,6 +80,8 @@ template<int N> struct Matrix
 
     void print() const
     {
+        using std::printf;
+
         for (int j = 0; j < N; j++)
         {
             for (int i = 0; i < N; i++)

test/math/remez-solver.h

@@ -258,6 +258,8 @@ public:
 
     void PrintPoly()
     {
+        using std::printf;
+
         /* Transform Chebyshev polynomial weights into powers of X^i
          * in the [-1..1] range. */
         real bn[ORDER + 1];

test/math/remez.cpp

@@ -21,8 +21,7 @@
 
 #include "core.h"
 
-using namespace lol;
-using namespace std;
+using lol::real;
 
 #include "remez-matrix.h"
 #include "remez-solver.h"