Add start of selection api, support for HasSelection, SelectAll and DeleteSelection along with documentation. Implement for IE and WebKitGTK and add stubs for OSX WebKit.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/SOC2011_WEBVIEW@68195 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/webview_ie.cpp

@@ -564,6 +564,26 @@ bool wxWebViewIE::IsEditable()
         return false;
 }
 
+void wxWebViewIE::SelectAll()
+{
+    ExecCommand("SelectAll");
+}
+
+bool wxWebViewIE::HasSelection()
+{
+    IHTMLDocument2* document = GetDocument();
+    IHTMLSelectionObject* selection;
+    document->get_selection(&selection);
+    BSTR type;
+    selection->get_type(&type);
+    return wxString(type) != "None";
+}
+
+void wxWebViewIE::DeleteSelection()
+{
+    ExecCommand("Delete");
+}
+
 bool wxWebViewIE::CanExecCommand(wxString command)
 {
     IHTMLDocument2* document = GetDocument();