Fixed warnings
Make scons understand different target architectures. Added help.
Use target=x86_32 for now. Thanks Nils for the initial work.
64-bit build fixes.
Type cleanup for 64-bit.
(Modified by Julian to be less intrusive. Don't use size_t for simple for loops.)
Fix printf warnings/breakage.

This a bit ugly, because there are no useful printf modifiers for size_t or uintptr_t, so we liberally cast them to size_t.
Shut up interrupt handling.
Rudimentary VGA support (issue #7). Experimental disk support (pass -d disk-image to seoul). Largely untested network support (pass -t tap-device to seoul).
Exit on q. Implemented reboot and debug.
Revert "Timer programming: take care that delta might be 0."

This reverts commit f7c1895f7f4cc9faa54858a8809677e6f7110689, because it caused an endless loop.
Hopefully fixed timeout handling.
Fixed startup race condition.