L4 update

I wrote a complete uart driver in C++. Added parts of it (polled mode, it doesn't need irqs) to kernel debugger for L4. Compiled the final image, loaded it in axd and I was able to run it partially.

The problem is that the kernel image does not contain any symbols, because dite discards all of them. I got good replies in L4 mailing list. It seems I don't have to have an elf loader bundled with my image since axd is capable of loading elf images, but I'm not sure yet whether I need dite still. I should need it, because the bootinfo should be patched and hello + sigma + kernel still needs to be put together (using dite?).

I read through the elf specs, It should be easy enough to copy symbols before dite, and then patch them after dite, to the final image. We'll see.