Merge branch 'bugfix_GNU_SOURCE' of github.com:fgeorgatos/easybuild-framework into bugfix_GNU_SOURCE
add _SOURCE suffix to XORG source url constants
add support for nameletter and nameletterlower templates, test via unit tests
Merge branch 'bugfix_GNU_SOURCE' of github.com:fgeorgatos/easybuild-framework into bugfix_GNU_SOURCE