Added classes to manage simple tabular data of known structure using a

popup containing a wxGrid object.

BasePicker : Abstract class adding a popup to wxPickerBase  styled with
a wxTextCtrl.
BaseGridPicker : Abstract class adding a wxGrid in the popup.

JsonGridPickerCtrl : UI control storing the tabular data in a JSON
array.
LBoundJsonGridPicker : connect JsonGridPicker to database.
LGridJsonCellEditor : use LBoundJsonGridPicker in other wxGrid objects.
LGridJsonCellRenderer : render cell JSON data.

XmlGridPickerCtrl : UI control storing the tabular data in as XML
document.
LBoundXmlGridPicker : connect XmlGridPicker to database.
LGridXmlCellEditor : grid editor for LBoundXmlGridPicker.
LGridXmlCellRenderer : grid renderer for LBoundXmlGridPicker.

JsonHelper and XmlHelper : for applications to quickly get intent value
from database data..

The structure of managed tabular data :

Column 1 : Intent - this is what we want to store/edit. This can be
telephone numbers, email addresses, instant messaging addresses...
any single line piece of information that can exist many times for one
entity (person, company...).
Column 2 : Type - A short description of the intent : 'Home, Work,
Mobile, Fax, Other...'. It is displayed in a non editable wxComboBox.
Column 3 : Preferred - One line of data can be selected as the preferred
one. It is not mandatory, but it must be a single choice.
Column 4 : Notes - single line notes.

Adjust sql scripts and L7.dox.
Applied ANSI formatting style to all files.

Other changes :

Work around a nasty misbehavior.
Grid columns edited by a translated combobox expect full string
data as cell values. LResultSet::BEData() will report these mapped strings,
instead of database real data. LBoundComboBox::IsDirty() will always be
true even if the editor is unchanged once created.
Simplest workaround : disconnect m_BoundComboBox if unchanged.

LGridTextEditor::ProvideFormEditor() : set the form editor's value
explicitely.; wxTextCtrl does not interpret data it receives

LBoundControl::SetNull must be void.

LBoundGrid : Unbind:: instructions should limit to the widget's id, like Bind::

LConnection::GetReturnedKeys should return NULL.
LConnection::SetData should return void.

Notes : wxJSON must be configured with the same prefix as wxWidgets,
here /usr/local/{wxWidgets,wxWidgets-Release}.

L7/special/BasePicker.h

@@ -0,0 +1,63 @@
+/* 
+ * File:   BasePicker.h
+ * Author: SET - nmset@netcourrier.com
+ * License : LGPL version 2.1
+ * Copyright SET, M. D. - © 2014
+ *
+ * Created on December 7, 2019, 9:24 PM
+ */
+
+#ifndef BASEPICKER_H
+#define BASEPICKER_H
+
+#include <wx/wx.h>
+#include <wx/pickerbase.h>
+#include <wx/popupwin.h>
+
+/**
+ * Abstract class adding a popup to wxPickerBase styled with
+ * a non-editable wxTextCtrl. It manages the popup's position and size also.
+ * The picker control is a wxButton that shows the popup.
+ */
+class BasePicker : public wxPickerBase
+{
+    DECLARE_CLASS(BasePicker)
+public:
+    BasePicker(wxWindow *parent,
+               wxWindowID id,
+               wxSize popupSize = wxDefaultSize,
+               const wxString& text = wxEmptyString,
+               const wxPoint& pos = wxDefaultPosition,
+               const wxSize& size = wxDefaultSize,
+               long style = wxPB_USE_TEXTCTRL,
+               const wxValidator& validator = wxDefaultValidator,
+               const wxString& name = wxButtonNameStr);
+    virtual ~BasePicker();
+
+    virtual void UpdatePickerFromTextCtrl() = 0;
+    virtual void UpdateTextCtrlFromPicker() = 0;
+
+private:
+
+protected:
+    wxPopupTransientWindow * m_popup;
+    wxSize m_popupSize;
+    /**
+     * A new popup is always created. Any previous popup is deleted.
+     * It binds to OnPopupHidden().
+     */
+    virtual void CreatePopup();
+    /**
+     * Shows the popup managing its position and size.
+     * <br/><br/>
+     * If m_popupSize.GetWidth() < 0, the popup's width is set to the control's
+     * width.
+     * <br/>
+     * If m_popupSize.GetHeight() < 0, it defaults to 300.
+     */
+    virtual void DoShowPopup();
+    virtual void OnPopupHidden(wxShowEvent& evt) = 0;
+};
+
+#endif /* BASEPICKER_H */
+