* Added a FixedWidthPointer template class which uses 64-bit storage to hold
a pointer. This is used in place of raw pointers in kernel_args.
* Added __attribute__((packed)) to kernel_args and all structures contained
within it. This is necessary due to different alignment behaviour for
32-bit and 64-bit compilation with GCC.
* With these changes, kernel_args will now come out the same size for both
the x86_64 kernel and the loader, excluding the preloaded_image structure
which has not yet been changed.
* Tested both an x86 GCC2 and GCC4 build, no problems caused by these changes.