v0.1.0

The makefile now specifies a 24 MHz clock.
This is used in the delay macros and also now sets the system clock via trimming when flashing ("make upload").
Using a system clock around 24MHz works with all MCU having an internal RC oscillator.
area-8051/uni-STC@40d5cd3

Finally, this means STC15101/104 MCUs present in door sensors should work with the same hex file.