* Removed Pcb_Frame argument from BOARD() constructor, since it precludes
    having a BOARD being edited by more than one editor, it was a bad design.
    And this meant removing m_PcbFrame from BOARD.
  * removed BOARD::SetWindowFrame(), since BOARD::m_PcbFrame gone.
  * Removed the global BOARD_DESIGN_SETTINGS which was in class_board.cpp
  * Added BOARD_DESIGN_SETTINGS to the BOARD class, a full instance
  * A couple of dialogs now only change BOARD_DESIGN_SETTINGS when OK is pressed,
    such as dialog_mask_clearance, dialog_drc, etc.
  * Removed common/pcbcommon.cpp's int g_CurrentVersionPCB = 1 and replaced it
    with build_version.h's #define BOARD_FILE_VERSION, although there may be a
    better place for this constant.
  * Made the public functions in PARAM_CFG_ARRAY be type const.
    void SaveParam(..) const and void ReadParam(..) const
  * PARAM_CFG_BASE now has virtual destructor since we have various ways of
    destroying the derived classes and boost::ptr_vector must be told about this.
  * Pass const PARAM_CFG_ARRAY& instead of PARAM_CFG_ARRAY so that we can use
    an automatic PARAM_CFG_ARRAY which is on the stack.
  * PCB_EDIT_FRAME::GetProjectFileParameters() may no longer cache the array,
    since it has to access the current BOARD and the BOARD can change.
    Remember BOARD_DESIGN_SETTINGS are now in the BOARD.
  * Made the m_BoundingBox member private, this was a brutally hard task,
    and indicative of the lack of commitment to accessors and object oriented
    design on the part of KiCad developers.  We must do better.
    Added BOARD::GetBoundingBox, SetBoundingBox(), ComputeBoundingBox().
  * Added PCB_BASE_FRAME::GetBoardBoundingBox() which calls BOARD::ComputeBoundingBox()