destroy program in shader destructor

src/render/Shader.cpp

@@ -10,4 +10,11 @@ GLint CShader::getUniformLocation(const std::string& unif) {
     }
 
     return itpos->second;
+}
+
+CShader::~CShader() {
+    // destroy shader
+    if (program != 0) {
+        glDeleteProgram(program);
+    }
 }