Use wxCOL_WIDTH_AUTOSIZE instead of fixed column sizes. This doesn't fix
the initial sizer layout issue on wxWidgets 3.0 but at least resizing the
dialog has better column width behavior.
There are lot of places where constants are used in the KiCad UI
as "magic numbers". The most common one is "5", used in many
wxFormBuilder and manual UI constructions as the margin.
This commit provides a place for all UI to look up shared
constants and other functions, to help create a consistent UI using
functions that provide meaning and intent to these magic numbers.
Jeff Young
Wayne Stambaugh
John Beard