Power improvements (#114)

Boards/M5stackShared/Source/hal/M5stackPower.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include "hal/Power.h"
+#include <memory>
+
+using namespace tt::hal;
+
+class M5stackPower : public Power {
+
+public:
+
+    M5stackPower() {}
+    ~M5stackPower() {}
+
+    bool supportsMetric(MetricType type) const override;
+    bool getMetric(Power::MetricType type, Power::MetricData& data) override;
+
+    bool supportsChargeControl() const { return true; }
+    bool isAllowedToCharge() const { return true; } /** We can call setChargingAllowed() but the actual value is unknown as it resets when re-plugging USB */
+    void setAllowedToCharge(bool canCharge);
+};
+
+std::shared_ptr<Power> m5stack_get_power();