Fix main function

test/tests/sawyercoding_test.cpp

@@ -1,5 +1,5 @@
 // Make MSVC shut up about M_PI
-#include <math.h>
+#include <cmath>
 
 extern "C" {
 #include "util/sawyercoding.h"

test/tests/tests.cpp

@@ -7,7 +7,7 @@
 int main(int argc, char * * argv)
 { 
     testing::InitGoogleTest(&argc, argv);
-    RUN_ALL_TESTS(); 
+    return RUN_ALL_TESTS();
 }
 
 #endif