Import mdocml-1.13.1
Merge branch 'vendor/MDOCML'

Conflicts:
	contrib/mdocml/Makefile
	contrib/mdocml/mandoc.h
	contrib/mdocml/mdoc_validate.c
	contrib/mdocml/read.c
mdocml: compile and reapply some local changes
powerd: add an option to disable turbo mode