Merge pull request #567 from mehlis/tests-astyle

tests: use astyle to adopt current code style guide
fix call to err()
Merge pull request #566 from mehlis/examples-astyle

examples: use astyle to adopt current code style guide
handle select errors EAGAIN | EWOULDBLOCK in lpm
handle some should-be impossible paths
guard swapcontext in _native_syscall_leave
handle more errors and remove race condition in native_isr_entry
Don't unblock signals again.

A late signal could kill the process otherwise.
guard setitimer
block all signals per default
force-debug (eINT && in_isr) in DEVELHELP
dont err() but warn() if no thread exists in native_isr_entry
guard pre-err() warn() calls
Merge pull request #583 from LudwigOrtmann/native_signals

Native signals
shell: added a handler for mersenne twister