Improve TX and RX frequency input

[m0wtn]

It is currently difficult to manually enter TX and RX frequencies into the QSO tab within the main window. If I highlight the current frequency and start typing a new frequency only the digits before the decimal point are accepted (MHz). To enter the digits after the decimal point (kHz) I need to highlight (select) a single digit and then type in a new digit. I need to do this for every/all digits after the decimal point. When frequencies are automatically being populated by WSJT-X for example then this is not an issue but if the user is entering all data manually, such as when manually logging voice contacts then this is a problem and wastes a lot of the users time. Could the frequency fields allow a complete frequency, such as "14.263" to be directly entered with the keyboard?

Also the up/down arrows associated with the frequency fields currently increase and decrease the frequency by 1 MHz, would it be possible to change this so that frequencies can instead be increased/decreased by 1 kHz?

[conorpeterson]

This is a duplicate of issue #378 except for the suggestions on changing the frequency by kHz with the arrow keys.

[barjac]

Also a duplicate of #448

[ea4k]

Duplicated #378