- Added const (#313)

# Conflicts:
#	src/ModbusAPI.h

Author: lmartorella

src/ModbusAPI.h

@@ -128,9 +128,9 @@ class ModbusAPI : public T {
 	uint16_t readWriteHreg(TYPEID slaveId, uint16_t readOffset, uint16_t* readValue, uint16_t readNumregs, uint16_t writeOffset, uint16_t* writeValue, uint16_t writeNumregs, cbTransaction cb = nullptr, uint8_t unit = MODBUSIP_UNIT);
 
 	template <typename TYPEID>
-	uint16_t rawRequest(TYPEID ip, uint8_t* data, uint16_t len, cbTransaction cb = nullptr, uint8_t unit = MODBUSIP_UNIT);
+	uint16_t rawRequest(TYPEID ip, const uint8_t* data, uint16_t len, cbTransaction cb = nullptr, uint8_t unit = MODBUSIP_UNIT);
 	template <typename TYPEID>
-	uint16_t rawResponce(TYPEID ip, uint8_t* data, uint16_t len, uint8_t unit = MODBUSIP_UNIT);
+	uint16_t rawResponce(TYPEID ip, const uint8_t* data, uint16_t len, uint8_t unit = MODBUSIP_UNIT);
 	template <typename TYPEID>
 	uint16_t errorResponce(TYPEID ip, Modbus::FunctionCode fn, Modbus::ResultCode excode, uint8_t unit = MODBUSIP_UNIT);
 };
@@ -475,7 +475,7 @@ uint16_t ModbusAPI<T>::readWriteHreg(TYPEID ip, \
 template <class T>
 template <typename TYPEID>
 uint16_t ModbusAPI<T>::rawRequest(TYPEID ip, \
-			uint8_t* data, uint16_t len,
+			const uint8_t* data, uint16_t len,
 			cbTransaction cb, uint8_t unit) {
 	free(this->_frame);
 	this->_frame = (uint8_t*)malloc(len);
@@ -489,7 +489,7 @@ uint16_t ModbusAPI<T>::rawRequest(TYPEID ip, \
 template <class T>
 template <typename TYPEID>
 uint16_t ModbusAPI<T>::rawResponce(TYPEID ip, \
-			uint8_t* data, uint16_t len, uint8_t unit) {
+			const uint8_t* data, uint16_t len, uint8_t unit) {
 	free(this->_frame);
 	this->_frame = (uint8_t*)malloc(len);
 	if (!this->_frame)