[Axl] Change notification: axl-bool-removal-01

[Francis Brosnan Blazquez]

        #####################################
        ####     Change notification     ####
        #####################################

    Change Id: axl-bool-removal-01
 Project name: Axl library
  Included in: 0.5.4
       Status: NOTIFY
       Author: Francis Brosnan Blázquez

Motivation
~~~~~~~~~~

Current c++ users consuming the Axl Library API have some issues to
properly use bool type. Because this type is built-in supported by c++
language, and new C versions (C99), but modeled with 8 byte, this
produce memory align problems with C ansi compiled versions of Axl
that models the bool type as an int (4 or 8 bytes according to the
platform) causing the value receive to not be properly
handled/read/returned.

The change intention is to remove the bool type definition, leaving C
users in the same situation until now: they keep on using int type,
but, at the same time, c++ users can interface with the API without
needing to create wrappers.

Change Description
~~~~~~~~~~~~~~~~~~

1) "bool" type definition in axl_decl.h header is removed. Until now it
   was a typedef to int. 

2) "false" and "true" definitions are kept and they are fully
   usable. Both values evals to 0 and 1. These values will be the API
   convention to handle boolean values internally.

3) All functions receiving or returning bool values now receive or
   return int. 

Solution to incompatibility
~~~~~~~~~~~~~~~~~~~~~~~~~~~

C users: because the typedef was a "cosmetic" definition making the
         API to look better, no change is required. In fact, the API
         was already expecting to receive an int value. Because in
         many cases "false" and "true" definitions from axl_decl.h was
         used, current code is BINARY and API compatible. So, no
         change is required.

c++ users: they won't need to use wrappers around functions using bool
           type from Axl Library for newly written code. For wrappers
           already written, they will still work since the Axl Library
           API is expecting int as in previous releases.

References
~~~~~~~~~~
[1] Axl library
    http://xml.aspl.es

[2] Axl library change notifications
    http://xml.aspl.es/doc.html

[3] Change notification definition
    http://www.aspl.es/change/change-notification.txt

[4] A discussion about int and bool type on Axl and Vortex API
    http://lists.aspl.es/pipermail/vortex/2008-October/000712.html

[5] An article about integer types
    http://home.att.net/~jackklein/c/inttypes.html
-- 
Francis Brosnan Blazquez <francis at aspl.es>
Advanced Software Production Line, S.L.