Add option for decimal places

[win98se]

Since a version update (long ago), now the frequency displays with 3 decimal places (e.g. 2196.478 MHz) instead of integer (e.g. 2196 MHz).

I recommend the developer(s) to add an option so that people can customize how many decimal places they want for the frequency indicator.

[fin-ger]

I think sane defaults would suffice. I suggest 2 decimal places for GHz, and no decimal places for MHz.

[fin-ger]

Update got reviewed and released.