Don't read/write or import/export Font "Height" property, redundant with "Size"

Also:
For log message styles (e.g. colorization) based on log level, don't apply
a different font (Name) or size. This just looks terrible when this is done
and I don't think any sysops want that. Keep each log window using the same
font face (name) and size, just allow the color and style (e.g. bold, italics)
to change based on log severity.

This does increase the confusion with the Properties->Customize->Log Fonts
as the "Change Font" dialog still allows the sysop to select/change a font
face and size, they're just not saved/used. I coudln't find a way to remove
or disable these from the displayed TFontDialog form.