* 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.

Pcbnew:
 * graphic_item_properties_base.fbp * dialog pad edit: make some strings more easier to translate.
 * global pad edition: fix a bug that change pad position instead of pad size (round pas only).
Eeschema:
 * fix a bug: new created wires were not alwaes shows until the screen was redrawn.

Modedit: add dialog to edit footprint body items. Fix also minor issues about footprint body items edition.