WX: Replace SetIcon with SetIcons(wxIconBundle)

Setting a single icon at a single resolution doesn't scale well,
Windows requires a 16x16 icon for the window and a 32x32/48x48 for
the taskbar. Providing all icons produces less pixellated results at
HiDPI.

Source/Core/DolphinWX/WxUtils.h

@@ -36,6 +36,9 @@ wxBitmap CreateDisabledButtonBitmap(const wxBitmap& original);
 void AddToolbarButton(wxToolBar* toolbar, int toolID, const wxString& label, const wxBitmap& bitmap,
                       const wxString& shortHelp);
 
+// Gets a complete set of window icons at all relevant sizes, use with wxTopLevelWindow::SetIcons
+wxIconBundle GetDolphinIconBundle();
+
 // Get the dimensions of the virtual desktop that spans all monitors.
 // Matches GetSystemMetrics(SM_XVIRTUALSCREEN), etc on Windows.
 wxRect GetVirtualScreenGeometry();