* new ui/DisplayDriver classes (just SSD1306Display impl for now)

* companion radio: now with optional UITask (enabled by DISPLAY_CLASS config in target/env)

src/helpers/ui/SSD1306Display.h

@@ -0,0 +1,37 @@
+#pragma once
+
+#include "DisplayDriver.h"
+#include <Wire.h>
+#include <Adafruit_GFX.h>
+#include <Adafruit_SSD1306.h>
+
+#ifndef PIN_OLED_RESET
+  #define PIN_OLED_RESET        21 // Reset pin # (or -1 if sharing Arduino reset pin)
+#endif
+
+#ifndef DISPLAY_ADDRESS
+  #define DISPLAY_ADDRESS   0x3C
+#endif
+
+class SSD1306Display : public DisplayDriver {
+  Adafruit_SSD1306 display;
+  bool _isOn;
+  uint8_t _color;
+
+public:
+  SSD1306Display() : DisplayDriver(128, 64), display(128, 64, &Wire, PIN_OLED_RESET) { _isOn = false; }
+  bool begin();
+
+  bool isOn() override { return _isOn; }
+  void turnOn() override;
+  void turnOff() override;
+  void startFrame(Color bkg = DARK) override;
+  void setTextSize(int sz) override;
+  void setColor(Color c) override;
+  void setCursor(int x, int y) override;
+  void print(const char* str) override;
+  void fillRect(int x, int y, int w, int h) override;
+  void drawRect(int x, int y, int w, int h) override;
+  void drawXbm(int x, int y, const uint8_t* bits, int w, int h) override;
+  void endFrame() override;
+};