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

* when a footprint has  many pads having the same pad name, only the first pad was connected to the net

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.

All: added a standard exit dialog called by int DisplayExitDialog( wxWindow* aParent, const wxString& aMessage )
Called when closing pcbnew, cvpcb and eeschema.
Minor code cleaning: remove duplicate or not used strings (mainly file extensions and wildcards)

wxWidgets 2.9 knows wxSVGFILEDC device context.
Unfortunately, arcs are drawn as pies (this is a feature, not a bug).
This is not correct for Kicad.
So Kicad has its own wxSVGFILEDC (named KicadSVGFileDC) that is basically the same as wxSVGFILEDC,
but with arcs drawn as arcs, not pies.
Note also under wxWidgets 2.8 does not know wxSVGFILEDC , so kicad had already its own SVG device context.

other minor fixes.

any configuration overrides.

Call SetDesignSettings() in PCB_BASE_FRAME::ReadSetup().

Pcbnew: Hight contrast mode: commit last patch from Miguel Angel Ajo Pelayo, which also  fixes an old bug.
All: prepare better compatibility with wxWidgets 2.9.4. Works fine with 2.8.x (I hope...)

ModEdit (and ModView): make "invisible" texts visible. They are not visible in  the board editor, but must be visible in the footprint editor.
Minor doc update.

* Convert Eeschema from manually linked list to DLIST for storing
  SCH_ITEM objects.
* Add helper functions to SCH_SCREEN for appending list of SCH_ITEM
  objects.
* Fix bug in wire editing code for accurate undo/redo behavior.
* Add member to DLIST to append another DLIST.
* Other minor code cleaning.

Pcbnew: zone filling: fix broken thermal relief shape for oval pads. mainly noticeable for oval pads having very different X and Y sizes.

* Pcbnew: in hight contrast mode the 'V' hotkey did not always refresh the screen.
* Eeschema: incorrect print scale when the option 'Show page limits' is disable.

    derived classes' implementations of these functions become non virtual and
    can be truly _inlined_ for speed!  All GetPosition() in derived classes were also
    changed to return const wxPoint&, that is, a reference rather than a
    full copy of the position wxPoint. There was no need for polymorphism in
    {Get,Set}Position() since we never call these functions via generic pointer.
  * Remove BOARD::{Get,Set}Position() since they were only there to satisfy
    the pure virtuals established in BOARD_ITEM, which are now gone.
  * Added const wxPoint& CPolyLine::GetPos(), made CPolyLine::Get{X,Y}() inline.
  * Derive CPolyPt from wxPoint so we can return "const wxPoint&" fromt
    CPolyLine::GetPos().

Eeschema: Viewlib is now accessible from Libedit (to browse libs or load a component to edit)
Libedit: uses now the same dialog as the schematic editor to load a component
Some code cleaning.

    which is in turn already within BOARD.
  * encapsulate class D_PAD with accessors, making data private.
  * make D_PAD::GetBoundingRadius() do its longer calculation lazily, based on
    m_boundingRadius == -1.