sixtracklib/common: Bugfixing in NS(Buffer) API
sixtracklib/common: Bugfixing in NS(Buffer) API

- The NS(Buffer_allocate_generic) function did not initialize the
  allocated slab of memory with zeros, thus passing a memory block
  with potentially non-zero data to the init functions.

  This could cause some problems, hence at least the header (as of this
  writing: the first 64 bytes of the memory slab) should be set to 0 to
  avoid triggering spurious remappings.

  The fix here attempts to zero-out the whole slab since there might be
  an attempt to force a data section alignment by increasing the header
  length -> i.e. we can't be sure that only the first N Bytes are
  required for the header.

SixTrack/SixTrackLib,SixTrack/SixTrackLib,SixTrack/SixTrackLib,SixTrack/SixTrackLib