Add wxIntegerValidator and wxFloatingPointValidator classes.

Add validators for integer and floating point numbers.

Add an example of their use to the validate sample as well as a new unit test
and documentation for them.

Use the new classes instead of wxTextValidator in wxGrid code.

Closes #12166.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66714 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

tests/test.bkl

@@ -199,6 +199,7 @@
              -->
             net/socket.cpp
             sizers/boxsizer.cpp
+            validators/valnum.cpp
             window/clientsize.cpp
             window/setsize.cpp
             xml/xrctest.cpp