refactor(preload/bhi): Make app more pythonic

This patch makes the BHI160 app more pythonic and fixes a few
bugs/issues:

- An exception (including KeyboardInterrupt) will trigger the sensor to
  be closed again.  Otherwise you'd get strange behavior trying to
  reopen then afterwards.
- Use simple_menu.button_events() instead of home-cooked solution.  This
  should hopefully make the code more future-proof.
- Fix overlapping text caused by the font-rendering changes.

Signed-off-by: Rahix <rahix@rahix.de>

preload/apps/bhi160/__init__.py

 import bhi160
-import display
-import utime
 import buttons
-
-disp = display.open()
-sensor = 0
-
-sensors = [
-    {"sensor": bhi160.BHI160Orientation(), "name": "Orientation"},
-    {"sensor": bhi160.BHI160Accelerometer(), "name": "Accelerometer"},
-    {"sensor": bhi160.BHI160Gyroscope(), "name": "Gyroscope"},
-    {"sensor": bhi160.BHI160Magnetometer(), "name": "Magnetometer"},
+import color
+import contextlib
+import display
+import itertools
+import simple_menu
+
+STATUS_COLORS = [
+    color.RED,
+    # Orange
+    color.RED * 0.5 + color.YELLOW * 0.5,
+    color.YELLOW,
+    color.GREEN,
 ]
 
-while True:
-    # Read and print sample
-    samples = sensors[sensor]["sensor"].read()
-    if len(samples) > 0:
-        disp.clear()
-        sample = samples[0]
+with contextlib.ExitStack() as cx:
+    disp = cx.enter_context(display.open())
 
-        color = [255, 0, 0]
-        if sample.status == 1:
-            color = [255, 128, 0]
-        elif sample.status == 2:
-            color = [255, 255, 0]
-        elif sample.status == 3:
-            color = [0, 200, 0]
+    args = {"sample_rate": 10, "sample_buffer_len": 20}
 
-        disp.print(sensors[sensor]["name"], posy=0)
-        disp.print("X: %f" % sample.x, posy=20, fg=color)
-        disp.print("Y: %f" % sample.y, posy=40, fg=color)
-        disp.print("Z: %f" % sample.z, posy=60, fg=color)
+    sensor_iter = itertools.cycle(
+        [
+            (cx.enter_context(bhi160.BHI160Orientation(**args)), "Orientation"),
+            (cx.enter_context(bhi160.BHI160Accelerometer(**args)), "Accel"),
+            (cx.enter_context(bhi160.BHI160Gyroscope(**args)), "Gyro"),
+            (cx.enter_context(bhi160.BHI160Magnetometer(**args)), "Magnetic"),
+        ]
+    )
+    sensor, sensor_name = next(sensor_iter)
 
-        disp.update()
+    for ev in simple_menu.button_events(timeout=0.1):
+        # Pressing the bottom right button cycles through sensors
+        if ev == buttons.BOTTOM_RIGHT:
+            sensor, sensor_name = next(sensor_iter)
 
-    # Read button
-    v = buttons.read(buttons.BOTTOM_RIGHT)
-    if v == 0:
-        button_pressed = False
+        samples = sensor.read()
+        if not samples:
+            continue
 
-    if not button_pressed and v & buttons.BOTTOM_RIGHT != 0:
-        button_pressed = True
-        sensor = (sensor + 1) % len(sensors)
+        sample = samples[-1]
+        col = STATUS_COLORS[sample.status]
 
-    utime.sleep(0.1)
+        disp.clear()
+        disp.print("{:^11s}".format(sensor_name), posy=0, posx=3)
+        disp.print("X:{: 9.4f}".format(sample.x), posy=20, fg=col)
+        disp.print("Y:{: 9.4f}".format(sample.y), posy=40, fg=col)
+        disp.print("Z:{: 9.4f}".format(sample.z), posy=60, fg=col)
+        disp.update()