Can not detect the initial state of half step rotary encoder correctly

The problem is that the code is unable to detect the initial state correctly, causing fail detection of the first half-step.

The way I solved the problem was to add this line:
```py
self._process_rotary_pins(None)
```
to the end of the `__init__` function of the `RotaryIRQ` class.

I don't know how it works, but it works. 