* configure.ac: Bump version to 1.6.

	* configure.ac: Bump version to 1.6.
	* doc/boot.S: Use tagged multiboot header.
	* doc/kernel.c (cmain): Parse tagged mbi.
	* doc/multiboot.texi: Selfishly added myself to authors.
	(Terminology): New types u_virt and u_phys.
	(Header address fields): Removed.
	(Header graphics fields): Likewise.
	(Header tags): New section.
	(Information request header tag): Likewise.
	(Address header tag): Likewise.
	(Console header tags): Likewise.
	(Module alignment tag): Likewise.
	(Header layout): Specify new common header part.
	(Header magic fields): Likewise.
	(Machine state): Updated magic value.
	(Boot information format): Changed to tagged structure.
	* doc/multiboot2.h: Changed to tagged format.
	* doc/src2texi: Handle more comments correctly.