[Bf-codereview] Interface for "Text" objects (bge) (issue 5504111)

[dfelinto at gmail.com]

Reviewers: bf-codereview_blender.org,

Description:
This patch creates an interface for ["Text"] properties in Font objects.

Interface:
http://www.pasteall.org/pic/show.php?id=23785

Simple test file:
http://www.pasteall.org/blend/10616

Code Explanation:
---------------
(1) it adds a toggle to add/remove a "Text" gameproperty.
  - internally this property is just another game property (so we can
find it within the game.properties lookup).
  - the property itself has no 'value', the interface shows the content
of ob.data.body instead (why? because gameproperties are per object,
while the text is per data).

(2) at BGE converter time it sets the current value of the
object.data.body to the ["Text"] property.

(3) if you change object.text (bge text property) it automatically
convert ["Text"] to a CStringValue.
*** that means if the original property was a CIntegerValue, it will be
converted to CStringValue forever ***

* the only to do I can think of is to add a warning at doversion time if
user has ["Text"] property for a Font object *

Please review this at http://codereview.appspot.com/5504111/

Affected files:
   release/scripts/startup/bl_ui/space_logic.py
   source/blender/editors/object/object_edit.c
   source/blender/makesrna/RNA_enum_types.h
   source/blender/makesrna/intern/rna_property.c
   source/gameengine/Converter/KX_ConvertProperties.cpp
   source/gameengine/Ketsji/KX_FontObject.cpp