Removed all the bools for axis in constructor and adapted it to bitwise flags

[maduranma]

Hi,

I opened this issue a few days ago: #243

As you agreed with the solution, I just adapted the constructor to accept it.
I had to move the constants to the header file (that's as well included in the .cpp file).

I kept the all on by default by setting it to 255 by default:

uint8_t hatSwitchCount = JOYSTICK_DEFAULT_HATSWITCH_COUNT,
        uint8_t includeAxisFlags = 255,
        uint8_t includeSimulatorFlags = 255);

Here is a demo of how it would work with the new constructor:

#include <Joystick.h>

Joystick_ Joystick = Joystick_(0x03, JOYSTICK_TYPE_JOYSTICK, 0, 0, JOYSTICK_INCLUDE_X_AXIS | JOYSTICK_INCLUDE_Y_AXIS, JOYSTICK_INCLUDE_NONE);

void setup() {
  Joystick.begin();
}

void loop() {
  Joystick.setXAxis(analogRead(A0));
  Joystick.setYAxis(analogRead(A1));
  
  delay(30);
}

Also, I added the constant JOYSTICK_INCLUDE_NONE as you might only want to have buttons, hat switches or just axis on the simulator flag or the axis flag. The value of this flag is 0 as that overrides the default 255 (all).

If you consider this good, I can write/correct the docs and examples.