- Add layout scheme to match PARTONS 
- Apply current style
- Update doxyfile
   - update titles
   - update mathjax script
   - make it similar to PARTONS doxyfile

- Generate tagfile to be used by NumA and PARTONS documentations.
- Some fixed to avoid conflicts with namespaces in documentation.

In Elementary_utils (trunk):
- Add the installation routines in CMakeLists.
- Add doxyfile.

In NumA++ (trunk):
- Add the installation routines in CMakeLists.
- Add FindElementaryUtils.cmake module and adapt CMakeLists.

In NumA++_Tests (trunk):
- Add FindElementaryUtils.cmake & FindNumA++.cmake modules and adapt CMakeLists.

In PARTONS (trunk):
- Add the installation routines in CMakeLists.
- Add FindElementaryUtils.cmake & FindNumA++.cmake modules and adapt CMakeLists.

In PARTONS_exe, PARTONS_release, PARTONS_Tests, PARTONS_Fits (trunk):
- Add FindElementaryUtils.cmake, FindNumA++.cmake & FindPARTONS.cmake modules and adapt CMakeLists.