This uses the new LEGACY_PLUGIN, so we can force more usage & testing of it
before ioascii.cpp and item_io.cpp are deleted, along with 
BOARD_ITEM::Save() and BOARD_ITEM::ReadDescr() associated functions.

* support for 3 terminal regulators
* add a data file management to store parameters for regulators ( name, vref value, Iadj value, type)
Needs some refinements, but it is already very useable.

 Commit dialog page setting patch from Alexander Zakamaldin

* Add s-expression Format() function to all objects derived from
  BOARD_ITEM.
* Add s-expression Format() function to base objects as required.
* Add functions to convert coordinates from base internal units
  (nanometers) to millimeter string for writing to s-expression
  file.
* Add temporary dummy conversion functions to prevent link errors
  until schematic and board object and action code can be separated
  into DSO/DLL.
* Add CMake build option to build Pcbnew with nanometer internal
  units.

Eeschema: one string with a bad char (\a, not useable in internationalized strings).
Dialog_page_settings: use not translated strings in code, so strings can be freely translated for the UI.
(Initial code was not working with existing translations)
Update 2 icons.

* BLOCK_SELECTOR class is not longer derived from EDA_ITEM.
* Encapsulate BLOCK_SELECTOR class member variables and add access methods.
* Move HandleBlockBegin() function from block_commande.cpp to drawframe.cpp.
* Remove virtual methods from top level derived objects per future
  coding policy change.
* Remove Doxygen copydoc statement from objects derived from EDA_ITEM
  since the comments are automatically copied to the derived object.
* Removed copy and pasted Doxygen comments from objects derived from
  EDA_ITEM.

class EDA_RECT: is no more derived from EDA_ITEM, just from EDA_RECT (reason: does not use anything in EDA_ITEM)
issue in cast to wxRect fixed (EDA_RECT accepts negative size, but not wxRect, so the wxRectcast  is normalized now).
This fixes some bugs.
A minor other bug fix in Pcbnew.

subclass DIALOG_SHIM support.
Tried dialog_drc but it has nesting problems due to use of DRCLISTBOX, which
needs to be put into its own header file to untangle.

Add include/dialog_shim.h and common/dialog_shim.cpp for use by wxformbuilder's "subclass a wxDialog" support.
This works, but in my version of wxformbuilder there is a bug which does not properly show the 
subclass property, even though it is still in play.  This happens after saving then loading the *.fbp file.
So it is a nuisance bug, but does not affect functionality.

Remove 2 duplicate icons.
Minor cosmetic enhancements and fixes in popup menus.

Eeschema: fix a bug in bool SCH_LINE::MergeOverlap( SCH_LINE* aLine ): ends point of resulting segment incorrects.
remove unused icon files.

* Remove double Clone() function calls from all classes derived from
  EDA_ITEM.
* Lots of Doxygen comment warning fixes.

* All objects derived from EDA_ITEM now have consistent hit test method
  definitions.
* Remove double function calls from all classes derived from SCH_ITEM.
* Lots of Doxygen comment fixes.

* make 2 bitmaps more visible.
* fix incorrect screen redraw when rotating a component.
* netlist : the pcbnew advanced format can be now stored (persistant option) in project config.

  * Save all visibilities, layer and render, in BOARD and restore on load.

Ckecks more pad parameters in pad editor dialog (previously not tested, so a pad could have some very incorrect parameters)