Merge pull request #148 from Willem3141/master

Documentation: add "unimplemented" note to two functions
Finish symlink support in kernel

This allows you to open symlinks as if they were files
Start writing C headers, add kernel-headers target
Remove a bunch of internal stuff from kernel.inc
Improve naming conventions in display.h
Add defines.inc to kernel.inc
Drop display.h from kernel headers

We'll do this from userspace instead via libc
Fix macros in kernel.inc
Revert "Fix macros in kernel.inc"

This reverts commit 0fcb327bd2835015579d580e412a08acd2963f13.
Don't copy headers that don't exist
Added link port defines to constants.asm
Implement streamWriteByte
Remove test code

God fucking dammit
Implement streamWriteWord
Export streamWrite{Byte,Word} to userspace
Remove unused string
Fixed increment-16-and-test in streamWriteByte
Implement streamWriteBuffer
Export streamWriteBuffer to userspace
Fix error when resolving symlinks