Reviewed the dummy function to declare the dependencies and export the
collected dependencies to the client projects.

If a subdirectory in a derived project tries to create the same module
as another subdirectory in the used project, the configuration will stop
with an error.

This is needed to ensure that the current build directories are
prepended to the paths defined in the XML (to override libraries).

The regular "export" mechanism of CMake cannot be used because it
prevents the overriding of subdirs and it doesn't allow transitivity of
include directories.

The choice is to implement our own export mechanism that allow overrides
and exports all the special properties the framework is using
(transitive includes and libraries).

The main disadvantage is that the implicit transitive link has to be
reimplemented within our framework and thus we are bound to the
framework to create libraries, modules and executables.

TODO:
- the import of other projects (CMT 'use') has to be implemented and
  made recursive (the prototype uses hard-coded Gaudi to test)

disabled the default file-based logging in EnvConfig/log.conf

The tcmalloc package is special, because we do not link against the
library, but we need the LD_LIBRARY_PATH set to find it anyway.

Imported the Python code from the LHCb package EnvConfig.

generate an XML file with description of the changes

Simplified the creation of custom global targets with two the macros
  - gaudi_global_target_append
  - gaudi_global_target_get_info

It has to be re-implemented using the EnvConfig package written
by the LHCb Summer Student.

It's not possible to fix the order in which install steps are done, so
we cannot ensure that the zipping is executed _after_ the installation
of all Python files.

I added a custom target (python.zip) as a short-cut to call the command,
but it has to be run by hand.

See http://public.kitware.com/Bug/view.php?id=8438

resolved conflict in installation of __init__.py
removed duplicate install of unit tests

Modified the way __init__.py are created.

The QMTest are executed as a single CTest and always succeed,
even if the tests inside fail (limit of the wrapper we use).

The environment is forced and only partially dynamic (to be fixed).

(and cleaned up gaudi_install_headers)

- gaudi_get_packages
- gaudi_add_python_module (was GAUDI_PYTHON_MODULE)
- gaudi_add_executable (was GAUDI_EXECUTABLE)
- gaudi_add_unit_test (was GAUDI_UNIT_TEST)

Removed the build of the dictionaries from GaudiContrib and added
functions to in GaudiProjectConfig to extend the dictionary builds.

Modified the names of the functions GAUDI_{LINKER,COMPONENT}_LIBRARY to
use CMake naming conventions: gaudi_add_{library,module}.
The options have been renamed too:
 - LIBRARIES -> LINK_LIBRARIES
 - USE_HEADERS -> INCLUDE_DIRS

Factored out the code to expand the list of source patterns as a macro
(gaudi_expand_sources).

Removed some useless code and code that needs to be re-added.