clean up

move syscalls to syscalls.c
declare (some) internal variables to native_internal.h
make cpu_switch_context_exit safer
make tap faster (real_read instead of native/read)
add name to sysconfig
bring back the name for the sockaddr6_t struct this is necceccary for the #define sockaddr_in6 socka6 hack to work
Merge branch 'socka6_hack' into working
Merge branch 'simple_list' into working
Merge branch 'native_fixes' into working
Revert "correct byte order for UDP length field"

This reverts commit a94d4a0b46e0f0948323f204b9cf0f50985b88a5.
Revert "fixed byte order for ieee802.15.4 frame"

This reverts commit f6c37b0b4fab35ab50aa9095f1c584fb74f92d0a.