♻️ (engine.cpp,onCreate.cpp,showFps.cpp,CMakeLists.txt): remove unused headers and clean up build file

Remove unnecessary #include directives from engine.cpp, onCreate.cpp,
and showFps.cpp to reduce compile time and improve readability.
Also delete extraneous blank lines in CMakeLists.txt for cleaner
configuration.

CMakeLists.txt

@@ -11,8 +11,6 @@ add_executable(CoursOpenGl ${LIB_HEADERS} ${HEADERS} ${SRC})
 find_package(OpenGL REQUIRED)
 find_package(glfw3 3.4 REQUIRED)
 
-
 target_include_directories(CoursOpenGl PUBLIC ${CMAKE_SOURCE_DIR}/include)
 target_link_libraries(CoursOpenGl glfw OpenGL::GL -lGLU ${GLEW_LIBRARIES})
 target_link_directories(CoursOpenGl PUBLIC .)
-

src/core/engine.cpp

@@ -1,7 +1,6 @@
 #include "engine.h"
 #include <cstdlib>
 #include <iostream>
-#include <utility>
 #include <vector>
 
 djalim::OpenGlEngine::OpenGlEngine(const char* title, int width, int height) {

src/onCreate.cpp

@@ -1,7 +1,5 @@
 #include "engine.h"
 #include "Texture2D.h"
-#include <iostream>
-#include <vector>
 
 void djalim::OpenGlEngine::onCreate(){
     glEnable(GL_DEPTH_TEST);

src/utils/showFps.cpp

@@ -1,4 +1,5 @@
 #include "engine.h"
+#include <sstream>
 
 void djalim::OpenGlEngine::showFps()
 {