constructor takes a keyword table, so it can be used for arbitrary DSN
    syntax files of your own chosing.  Simply create an enum {} with all your
    unique tokens in it.  Then create a KEYWORD table.  See SPECCTRA_DB::keywords[].
    The reason you want an enum is to give the C++ debugger better type information
    so it can show symbolic integer symbols.
  * Factored out common richio.cpp and richio.h
    which is what DSNLEXER uses.
  * Fixed some minor issues with reading circuit descriptor from a *.dsn file.

  * Moved ReturnLayerName() to static BOARD::GetDefaultLayerName() and migrated
    to a Specctra DSN compatible default layer naming scheme:
        Component becomes Front, Copper becomes Back.
  * set_color.h: Cmp becomes Front, Cu becomes Back.
  * D_PAD::DisplayInfo() changed to use actual copper layer names.
  * more layer setup dialog work, moved all programmatic wxControl instantiation
    into the wxFormbuilder environment, but this is fraught with danger:
    wxFlexGridSizer used the tallest control to establish the row heights, so
    be careful about changing control borders in the scroll panel. The vertical
    size can explode since just a couple of pixels times the number of rows
    is substantial.  Currently I am setting a 5 pixel border only left, top, and right
    but not bottom.
  * Set copper layer count is back in place as a hack until I can get the enabled
    layer bit map fully operational.

* Fixed EESchema options dialog focus bug so escape key now works in GTK.
* Rename schematic objects for improved readability.
* Fixed GCC compiler warnings in plot code.
* Added paragraph in UIpolicies.txt about setting dialog box sizes.
* Lots of message box string clean up.

* Replace schematic editor options dialog with wxFormBuilder version.
* Fix ugly wxGTK sizer hack in pin properties dialog.
* Set dialog minimum size after initial fit to prevent dialog controls
  from being obscured when resizing.
* Move bitmaps in annotate dialog for cleaner control alignment.

* Make cancel button delete new pin instance.
* Make pin redraw correctly to prevent display corruption.
* Prevent edited pin from being move on next left button click.
* Change pin edit property dialog focus to pin name edit text control.

* Complete comment translation for all EESchema source files.
* Complete comment translation for all 3D viewer source files.
* Rename class class_hierarchical_PIN_sheet to SCH_SHEET_PIN.
* Rename class DrawSheetStruct to SCH_SHEET.
* Tool tip capitalization fixes.
* Uncrustify and spell check comments and strings in all modified source
  files.

* Replaced library pin properties dialog with wxFormBuilder version.
* Remove DialogBlocks version of pin properties dialog.
* Add pin properties dialog support code to pin object.
* Create single event handler for displaying pin properties dialog.
* Remove left over DialogBlocks project file for annotate dialog.
* Fixed escape key bug in library editor new component dialog.
* Add GetUnitsLabel() to get human readable units for dialog labels.
* Translate French comments in all modified files.
* Some minor clean up of Doxygen comments.

pcbnew Rewrite the GUI relative to the tracks widths and vias diameters and drills selection and edition, for compatibility with new netclass approach.

See also changelog

* Replace all known instances of (const wxChar*) casts to GetChars() for
  wxWidgets 2.9 compatibility.
* Cleaned up get component dialog so last part gets saved on wild card
  selections.
* Remove redundant schematic component drawing code.
* Added SCH_COMPONENT constructor to create new component from library
  component object.
* Add message panel helpers to WinEDA_DrawFrame and update old message
  panel access code.
* Using library viewer to add component to schematic now respects unit
  and body style selection.

* Create single event handler for grid size events.
* Fix all frame windows to use new grid size event handler.
* Use offset relative to ID instead of ComboBox index to save last grid size.
* Move last grid size load/save setting into WinEDA_DrawFrame.
* Add equality and assignment operators the GRID_TYPE.
* Add current grid helper methods to BASE_SCREEN.
* Add GetPins helper to LIB_COMPONENT to replace GetNextPin where applicable.
* Add AppendMsgPanel helper to WinEDA_DrawFrame.
* Improve rounding for display of coordinates when millimeter units are selected.

Fixed problems in libedit and crashes when no component loaded

* Replace component library editor new component dialog using wxFormBuilder.
* Rename component library draw items to conform to current coding standards.
* Add GetWidth() method to component library draw objects.
* Add regular expression key word search capability to component library object.

pcbnew: more about netclass work

* Library component draw items now stored in Boost ptr_vector.
* Updated draw item object comparison to include greater and less than condition.
* Moved set parts per package code from component edit dialog to component object.
* Moved set alternate body style code from component edit dialog to component object.
* Tweaked component library file draw item sort order for improved file readability.
* Documented component object draw item sort ordering.
* Moved plot code to the appropriate library component and draw item objects.
* Fixed compiler type conversion warning in plot_common.h.

* Eliminate external direct manipulation of component draw item pointer.
* Add draw item remove, add, and locate methods to library component object.
* Remove redundant locate pin, field, and draw item code.
* Fix add new pin drawing bug that left initial pin draw in place.
* Improved best zoom calculations for small components.
* Library component bounding box calculation now includes fields.
* Removed unnecessary header file "libcmp.h".
* Fixed potential locate draw item bug in library editor hot key handler.