After I got working kconfig tool for my ESP8266 firmware, I can more effectively implement new kind of sensors. So, the firmware now supports these ones:
Button is special and most recent kind of sensor. It is asynchronous and interrupt driven. It is also be considered to be used as abstraction layer. In future realeases, it should handle other asynchronous devices, such as PIR motion detector. It just detect rising or falling edge and transmits MQTT update message. It is in experimental phase, but it can be very useful.
All necessary configuration steps are done via 'make menuconfig'. You can find more details on my wiki page.