Separated test suites into their individual modules

- Building per module only requires to have split test utility sections
- System module tests are always added, as the system module is always built

test/src/TestUtilities/System.cpp

@@ -0,0 +1,20 @@
+// Note: No need to increase compile time by including TestUtilities/System.hpp
+#include <SFML/System/String.hpp>
+#include <SFML/System/Time.hpp>
+#include <sstream>
+
+// String conversions for Catch framework
+namespace Catch
+{
+    std::string toString(const sf::String& string)
+    {
+        return string.toAnsiString();
+    }
+
+    std::string toString(sf::Time time)
+    {
+        std::ostringstream stream;
+        stream << time.asMicroseconds() << "us";
+        return stream.str();
+    }
+}