tar

* Ruby source code is now loaded as a tar archive instead of single
  files as multiboot modules.
GDT

+ Sets up a GDT.
kernel/build.rb clean

* Should remove initrd
Newline after status

* A newline should be emitted after printing the status update (such as
  “[ DONE ]”)
MRB_INT64

* Use 64 bit integers so there are no floating point operations just for
  setting up the GDT (which requires unsigned 32 bit integers).
! Fix INT..._MIN limits in stdint.h
FPU (and SSE) initialization

! It might be a good idea to initialize especially the FPU (via finit);
  loading the default SSE control word can't hurt either
Descriptor tables, IDT

* Unified x86 descriptor tables and their entries (the descriptors)
+ Added simple IDT support.