Allow scrolling by keyboard in search panel

Lets you quickly scroll through elements in the board, zooming and
selecting each

common/widgets/search_pane_tab.cpp

@@ -151,13 +151,18 @@ void SEARCH_PANE_LISTVIEW::OnColClicked( wxListEvent& aEvent )
 
 void SEARCH_PANE_LISTVIEW::OnChar( wxKeyEvent& aEvent )
 {
-    if( aEvent.GetKeyCode() == WXK_CONTROL_A )
+    switch( aEvent.GetKeyCode() )
+    {
+        case WXK_CONTROL_A:
         {
             // Select All
             for( int row = 0; row < GetItemCount(); row++ )
                 SetItemState( row, wxLIST_STATE_SELECTED, wxLIST_STATE_SELECTED );
+
+            break;
         }
-    else if( aEvent.GetKeyCode() == WXK_CONTROL_C )
+
+        case WXK_CONTROL_C:
         {
             // Copy to clipboard the selected rows
             if( wxTheClipboard->Open() )
@@ -186,6 +191,60 @@ void SEARCH_PANE_LISTVIEW::OnChar( wxKeyEvent& aEvent )
                 wxTheClipboard->SetData( new wxTextDataObject( txt ) );
                 wxTheClipboard->Close();
             }
+
+            break;
+        }
+
+        case WXK_DOWN:
+        case WXK_NUMPAD_DOWN:
+        {
+            // Move selection down
+            long focused = GetFocusedItem();
+            if( focused < 0 )
+                focused = 0;
+
+            if( focused < GetItemCount() - 1 )
+            {
+                if( !(aEvent.GetModifiers() & wxMOD_SHIFT) )
+                {
+                    int next = -1;
+
+                    while( ( next = GetNextSelected( next ) ) != wxNOT_FOUND )
+                        Select( next, false );
+                }
+
+                ++focused;
+                Focus( focused );
+                Select( focused );
+            }
+            break;
+        }
+        case WXK_UP:
+        case WXK_NUMPAD_UP:
+        {
+            // Move selection up
+            long focused = GetFocusedItem();
+
+            if( focused < 0 )
+                focused = 0;
+
+            if( focused > 0 )
+            {
+                if( !(aEvent.GetModifiers() & wxMOD_SHIFT) )
+                {
+                    int next = -1;
+
+                    while( ( next = GetNextSelected( next ) ) != wxNOT_FOUND )
+                        Select( next, false );
+                }
+
+                --focused;
+                Focus( focused );
+                Select( focused );
+            }
+
+            break;
+        }
     }
 }