Core examples (#11)

* Added core_input_keys example

* Added core_basic_window example

* Added core_input_mouse example

* Added core_input_mouse_wheel example

examples/core/core_input_keys.py

@@ -0,0 +1,47 @@
+"""
+
+raylib [core] example - Keyboard input
+
+"""
+from raylib.pyray import PyRay
+from raylib.colors import (
+    RAYWHITE,
+    DARKGRAY,
+    MAROON,
+)
+
+
+pyray = PyRay()
+
+
+# Initialization
+SCREEN_WIDTH = 800
+SCREEN_HEIGHT = 450
+
+pyray.init_window(SCREEN_WIDTH, SCREEN_HEIGHT,
+                  'raylib [core] example - keyboard input')
+ball_position = pyray.Vector2(SCREEN_WIDTH / 2, SCREEN_HEIGHT / 2)
+
+pyray.set_target_fps(60)  # Set our game to run at 60 frames-per-second
+
+
+# Main game loop
+while not pyray.window_should_close():  # Detect window close button or ESC key
+    # Update
+    if pyray.is_key_down(pyray.KEY_RIGHT): ball_position.x += 2
+    if pyray.is_key_down(pyray.KEY_LEFT): ball_position.x -= 2
+    if pyray.is_key_down(pyray.KEY_UP): ball_position.y -= 2
+    if pyray.is_key_down(pyray.KEY_DOWN): ball_position.y += 2
+
+    # Draw
+    pyray.begin_drawing()
+
+    pyray.clear_background(RAYWHITE)
+    pyray.draw_text('move the ball with arrow keys', 10, 10, 20, DARKGRAY)
+    pyray.draw_circle_v(ball_position, 50, MAROON)
+
+    pyray.end_drawing()
+
+
+# De-Initialization
+pyray.close_window()  # Close window and OpenGL context