CursorManager: Add support for Start and Select buttons for PyGamer.

[flom84]

Hi

I have been using CursorControl with PyGamer for a personal projects and being quite fond of this library. Unfortunately, there is no support for PyGamer's Select and Start buttons . This change makes it possible to check if either Select or Start button have been pressed. Implementation is similar to how buttons A or B states are handled.

I hope that this pull request would be useful for others as well.

[FoamyGuy]

Thanks for working on this @flom84. I tested start and select buttons successfully on PyGamer and the functionality of it looks good to me.

I think we should add the values in the dictionary for pybadge devices as well here:

Adafruit_CircuitPython_CursorControl/adafruit_cursorcontrol/cursorcontrol_cursormanager.py

Lines 82 to 89 in 43ff5c6

	self._pad_btns = {
	"btn_left": PYBADGE_BUTTON_LEFT,
	"btn_right": PYBADGE_BUTTON_RIGHT,
	"btn_up": PYBADGE_BUTTON_UP,
	"btn_down": PYBADGE_BUTTON_DOWN,
	"btn_a": PYBADGE_BUTTON_A,
	"btn_b": PYBADGE_BUTTON_B,
	}

self._pad_btns = {
    "btn_left": PYBADGE_BUTTON_LEFT,
    "btn_right": PYBADGE_BUTTON_RIGHT,
    "btn_up": PYBADGE_BUTTON_UP,
    "btn_down": PYBADGE_BUTTON_DOWN,
    "btn_a": PYBADGE_BUTTON_A,
    "btn_b": PYBADGE_BUTTON_B,
+  "btn_select": PYBADGE_BUTTON_SELECT,
+  "btn_start": PYBADGE_BUTTON_START,
}

Without these the update() function ends up raising this error:

Traceback (most recent call last):
  File "code.py", line 23, in <module>
  File "/lib/adafruit_cursorcontrol/cursorcontrol_cursormanager.py", line 166, in update
KeyError: btn_select

[flom84]

@FoamyGuy thank you for reviewing my code. I would add another commit with the changes requested.

[FoamyGuy]

Thank you!

These changes look good to me. Tested successfully on pygamer and pybadge