Import linker script
Describe branch.
Import build system.
Add prerequisites for Makefile, Makefile.built and Makefile.options
Merge branch 'linker-script' into boot

Conflicts:
	README.md
Import simple blinker.
Add paging and switch to higher half kernel
Switch to system mode at boot
Clear out BSS section
Turn OK LED on before kernel_main() and off after and halt.
Simple kernel that keeps a light on for a while

Conflicts:
	README.md
Add .init_array and sort sections.
Prepare for constructors
Fix base address of GPIO to higher half.
Add constructor handling.
Add support for constructors.
Start memory subsystem
Merge branch 'memory'

Conflicts:
	README.md
Create gpio branch
Import minimal memory management