* Remove internal units from BASE_SCREEN and it's derivatives.
* Remove internal units from EDA_DRAW_FRAME and it's derivatives.
* Use build time code to replace internal units conversions.
* Fix scaling bug in page layout sample window that I created in my
last commit.
* Move all convert from user to internal units into base_units.cpp.
* Remove internal units parameters from all moved conversion functions.
* Revise all source code that calls the moved conversion functions.
* Remove internal units from all dialog text control helper classes.
* Move all convert from internal to user units functions into separate file.
* Remove internal units parameter from all moved conversion functions.
* Revise all source code that calls the moved conversion functions.
* Compile these conversion routines separately for the appropriate pcb or
schematic internal units.
* Move internal units specific status bar update code into the appropriate
application for updating the status bar.
* Move millimeter user units rounding function to common.cpp.
Wayne Stambaugh