added new startup model - set address after object creation - namely: added no arg constructor and method to set I2C address post object creation/contructor

Author: gigapod

src/SparkFunCCS811.cpp

@@ -233,6 +233,7 @@ CCS811::CCS811(uint8_t inputArg) : CCS811Core(inputArg)
 	CO2 = 0;
 }
 
+CCS811::CCS811() : CCS811(0){}
 //****************************************************************************//
 //
 //  Begin

src/SparkFunCCS811.h

@@ -70,6 +70,9 @@ class CCS811Core
 	CCS811Core(uint8_t);
 	~CCS811Core() = default;
 
+	void setI2CAddress(uint8_t address){
+		I2CAddress = address;
+	}
 	CCS811_Status_e beginCore(TwoWire &wirePort);
 
 	//***Reading functions***//
@@ -103,6 +106,7 @@ class CCS811 : public CCS811Core
 {
 public:
 	CCS811(uint8_t);
+	CCS811();
 
 	//Call to check for errors, start app, and set default mode 1
 	bool begin(TwoWire &wirePort = Wire);							  //Use the Wire hardware by default