The Stacks project

Improve chapter on hypercoverings

Made it more general so it works also for the hypercoverings exactly as
defined in Verdier's original.

LaTeX: \Mor

	Introduced a macro

	\def\Mor{\mathop{\rm Mor}\nolimits}

	and replaced all the occurences of \text{Mor} with \Mor.

LaTeX: Hom and SheafHom

	Introduced the macros

	\def\Hom{\mathop{\rm Hom}\nolimits}
	\def\SheafHom{\mathop{\mathcal{H}\!{\it om}}\nolimits}

	and replaced all the occurences of \text{Hom} and \textit{Hom}
	with these.

Started tags infrastructure

	new file:   scripts/add_tags.py
	modified:   scripts/functions.py
	new file:   tags/initial_tags
	new file:   tags/tags

Added Cech to cohomology spectral sequence for hypercoverings

	modified:   hypercovering.tex
	modified:   schemes.tex