change astylerc for astyle 2.0.4

brackets=attach becomes attach-namespaces
Change to 1tbs in .astylerc

adds backwards compatibility
addresses https://github.com/RIOT-OS/RIOT/pull/475#issuecomment-31639014
Merge pull request #475 from LudwigOrtmann/astyle-204

change astylerc for astyle 2.0.4