compile base_screen.cpp separately for {pcbnew,cvpcb} and eeschema, so we can diverge internal units at compile time, not runtime

Pcbnew: 2 minor enhancements

keep all the labelling tools together in the eeschema toolbar.

    sizes.  Tested with postscript output only.  Required minor file format changes
    to reflect the "portrait" setting.  common/dialogs/dialog_page_settings.cpp
    uses a checkbox but its name is "Landscape", which is inverted from portrait,
    but since it is the more common choice, I used that rather than portrait.
    The tooltip for that checkbox makes it clear.  No portrait mode is supported
    for "User" paper size.

Eeschema: Fix erroneous message [Read Only] after creating a new project, and obviously the corresponding schematic file does not yet exist (replaced by [no file])

Pcbnew: fix issue when KICAD_NANOMETER is defined: when zones use htcth to show zones areas, hatch lines were incorrectly calculated (hunded of thousand lines created)
Eeschema: fix issue in search: search not made in reference strings.
Minor fixes, code cleaning and comment enhancements.

* Remove unnecessary copy constructors from schematic and component
  library objects.
* Add comment to class definitions where the default copy constructor
  generated by the compiler was adequate.
* Add assignment operator to EDA_ITEM, SCH_ITEM, and all schematic
  objects where the default assignment operator generated by the
  compiler would not be adequate.

    Add shim class SCH_BASE_FRAME which introduces the data model SCH_SCREEN
    to the frame class hierarchy.

Eeschema: add compil option in sch_field.cpp to go back to old behavior for field texts justifications (this option is not activated)
Note: only vertical texts have a modified behavior.
Minor other changes.

* Move SCH_ITEM::Place() code into SCH_EDIT_FRAME so schematic item
  objects no longer have any knowledge of the schematic frame window
  or undo/redo containers.

Fix bug 910364: When a footprint saved in a .mod file is not on front layer and/or not with orientation 0 degree, the Module editor load it incorrectly.
note:  the Module editor save it with default orientation and layer, but the archive function does not, so some footprints can be not editable.
TODO: modify the Archive Function to use the default layer / orientation.

Pcbnew: fix a very minor issue.

* EDA_DRAW_PANEL completely encapsulated.
* Moved OSX m_overlay member from EDA_DRAW_PANEL to EDA_DRAW_FRAME where
  it is used.
* Doxygen comment warning fixes.

Eeschema: fix a minor issue.

Duplicate segments where created in drag command and netlist calculations.

* EDA_DRAW_FRAME completely encapsulated.
* Encapsulate the the low hanging fruit in EDA_DRAW_PANEL.

Better code in test connections in zones.
Very minor other fixes

* Add check box and flag to ignore replacing the component reference
  designator field.
* Fix a resizing bug when switching between the find and replace modes of
  the find/replace dialog.
* Fix replace component reference designator field bug.
* Force rebuild of search list when schematic is modified and the replace
  dialog is closed.
* Prevent finding the next item when the find/replace dialog is closed.
* Respect warp mouse pointer setting when closing find/replace dialog.
* Fix duplicate mnemonic control accelerator keys in find/replace dialog.

* EDA_RECT and EDA_ITEM completely encapsulated.
* Removed unnecessary EDA_ITEM member m_Selected and replaced functionality
  with SELECTED flag bit.

Minor cosmetic enhancements.
Pcbnew: more workd abput connection algorithms (work in progress)

* EDA_DRAW_FRAME completely encapsulated except for DrawFrame member.
* Moved members specific to Pcbnew from EDA_DRAW_FRAME to PCB_BASE_FRAME
  or PCB_EDIT_FRAME as appropriate.
* Replace EDA_TOOLBAR with wxAuiToolBar as EDA_TOOL bar provided no
  additional functionality and made code less readable.
* Remove EDA_TOOLBAR class definition from wxstruct.h and delete file
  wineda_toolbar.cpp.
* Rename tool bar members to something more descriptive since the
  horizontal and vertical references wont mean anything once the
  tool bars are movable.
* Lots of dead code removal.

* Enable replace toolbar button and menu entry.
* Improve find replace logging granularity.
* Fix find and replace dialog control hiding and disabling.
* Minor improvements to the SCH_FIND_REPLACE_DATA object.
* Move find collector list iterator into the collector object.
* Add visibility override flag to EDA_ITEM to temporarily show items that
  are hidden during find and replace.