Refactored MQTT payload handling into separate classes

src/hexutils.cpp

@@ -0,0 +1,23 @@
+#include "hexutils.h";
+
+String toHex(uint8_t* in) {
+	return toHex(in, sizeof(in)*2);
+}
+
+String toHex(uint8_t* in, uint8_t size) {
+	String hex;
+	for(int i = 0; i < size; i++) {
+		if(in[i] < 0x10) {
+			hex += '0';
+		}
+		hex += String(in[i], HEX);
+	}
+	hex.toUpperCase();
+	return hex;
+}
+
+void fromHex(uint8_t *out, String in, uint8_t size) {
+	for(int i = 0; i < size*2; i += 2) {
+		out[i/2] = strtol(in.substring(i, i+2).c_str(), 0, 16);
+	}
+}