Update Clang easyblock for Clang-3.3

You can now specify which targets to build (by default only X86)
Merge branch 'clang33' of github.com:wpoely86/easybuild-easyblocks into clang33
fix remarks
Merge pull request #3 from boegel/clang33

fix remarks in #248
Merge pull request #248 from wpoely86/clang33

Update Clang easyblock for Clang-3.3