Add wxActivityIndicator control.

This is a simple animated control indicating some program activity.

Provide native GTK+ (for > 2.20) and OS X implementations as well as a generic
one used under MSW.

Update the sample and the documentation.

samples/widgets/makefile.bcc

@@ -36,6 +36,7 @@ WIDGETS_CXXFLAGS = $(__RUNTIME_LIBS_7) -I$(BCCDIR)\include $(__DEBUGINFO) \
 	-I$(SETUPHDIR) -I.\..\..\include $(____CAIRO_INCLUDEDIR_FILENAMES_p) -I. \
 	$(__DLLFLAG_p) -I.\..\..\samples -DNOPCH $(CPPFLAGS) $(CXXFLAGS)
 WIDGETS_OBJECTS =  \
+	$(OBJS)\widgets_activityindicator.obj \
 	$(OBJS)\widgets_bmpcombobox.obj \
 	$(OBJS)\widgets_button.obj \
 	$(OBJS)\widgets_checkbox.obj \
@@ -263,6 +264,9 @@ $(OBJS)\widgets.exe: $(WIDGETS_OBJECTS)  $(OBJS)\widgets_sample.res
 	c0w32.obj $(WIDGETS_OBJECTS),$@,, $(__WXLIB_ADV_p)  $(__WXLIB_CORE_p)  $(__WXLIB_BASE_p)  $(__WXLIB_MONO_p) $(__LIB_SCINTILLA_IF_MONO_p) $(__LIB_TIFF_p) $(__LIB_JPEG_p) $(__LIB_PNG_p)   wxzlib$(WXDEBUGFLAG).lib wxregex$(WXUNICODEFLAG)$(WXDEBUGFLAG).lib wxexpat$(WXDEBUGFLAG).lib $(EXTRALIBS_FOR_BASE) $(__CAIRO_LIB_p) ole2w32.lib oleacc.lib import32.lib cw32$(__THREADSFLAG_5)$(__RUNTIME_LIBS_8).lib,, $(OBJS)\widgets_sample.res
 |
 
+$(OBJS)\widgets_activityindicator.obj: .\activityindicator.cpp
+	$(CXX) -q -c -P -o$@ $(WIDGETS_CXXFLAGS) .\activityindicator.cpp
+
 $(OBJS)\widgets_bmpcombobox.obj: .\bmpcombobox.cpp
 	$(CXX) -q -c -P -o$@ $(WIDGETS_CXXFLAGS) .\bmpcombobox.cpp