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.

with the new configuration style, the Find*.cmake modules
are independent from the toolchain and the version of the
toolchain has to be specified on the command line:

cmake -DCMAKE_TOOLCHAIN_FILE=cmake/toolchain/heptools-61b.cmake .

Install a platform-specific configuration file including details
about the linker and component libraries of the project.

Improved the platform-independent configuration file to present
the right variables (<project>_LIBRARY_DIRS etc.)

Use the special function "require" to declare the subdirectories
that need to be processed first.