So the new steals-focus protection stuff works well when there's a
focused control, but not as well when there's a modal dialog up which
happens not to have a focused control (or worse, a focusable control).
This adds a second mechanism for also checking to see if a modal dialog
is up (something that wxWidgets, true to form, makes very difficult).
Fixes https://gitlab.com/kicad/code/kicad/issues/6520
Replace SEVERITY_ERROR by RPT_SEVERITY_ERROR to avoid collision with a system definition.
Replace other SEVERITY_XXX by RPT_SEVERITY_XX for consistency.
Fix compil warnings and some other compil issues.
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.