Small doc updates, mainly wxDropTarget,

wxFileDlg now interprets a default dir of "." as
    the current working dir,
  dialog and frame honour "wxApp::DeleteFrameOnExit".


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@5134 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/filedlgg.cpp

@@ -579,7 +579,7 @@ wxFileDialog::wxFileDialog(wxWindow *parent,
         m_dialogStyle |= wxOPEN;
     
     m_dir = defaultDir;
-    if (m_dir.IsEmpty())
+    if ((m_dir.IsEmpty()) || (m_dir == wxT(".")))
     {
         char buf[200];
         m_dir = getcwd( buf, sizeof(buf) );