MSVC 2013 compatibility: added missing headers.

Not sure how this is done in GCC and Clang, they don't need ~60k LOC
<algorithm> just for std::max().

src/AbstractShaderProgram.cpp

@@ -24,6 +24,8 @@
 
 #include "AbstractShaderProgram.h"
 
+#include <algorithm> /* std::max(), needed by MSVC */
+
 #include "Math/RectangularMatrix.h"
 #include "Extensions.h"
 #include "Shader.h"

src/Math/Functions.h

@@ -25,6 +25,7 @@
 */
 
 #include <cmath>
+#include <algorithm> /* std::max(), needed by MSVC */
 #include <limits>
 #include <type_traits>
 #include <utility>

src/Shader.cpp

@@ -24,6 +24,7 @@
 
 #include "Shader.h"
 
+#include <algorithm> /* std::max(), needed by MSVC */
 #include <fstream>
 #include <Containers/Array.h>
 #include <Utility/Assert.h>