Added desktop cursor getter and setter functions (#1407)

* [core] Added desktop cursor getter and setter functions

* Example: Set mouse cursor in text input box

* Setup standard cursors _after_ GLFW window initialization

* Remove old `int GetMouseWheelMove` declaration

examples/text/text_input_box.c

@@ -43,6 +43,9 @@ int main(void)
 
         if (mouseOnText)
         {
+            // Set the window's cursor to the I-Beam
+            SetMouseCursor(MOUSE_CURSOR_IBEAM);
+
             // Get pressed key (character) on the queue
             int key = GetKeyPressed();
 
@@ -67,6 +70,10 @@ int main(void)
                 if (letterCount < 0) letterCount = 0;
             }
         }
+        else if (GetMouseCursor() != MOUSE_CURSOR_DEFAULT)
+        {
+            SetMouseCursor(MOUSE_CURSOR_DEFAULT);
+        }
 
         if (mouseOnText) framesCounter++;
         else framesCounter = 0;