The Stacks project

New macro: \Ext

Fixes

Thanks to Fan. See
http://stacks.math.columbia.edu/tag/08N2#comment-380

LaTeX: \Ob

	Introduced a macro

	\def\Ob{\mathop{\rm Ob}\nolimits}

	and replaced any occurence of \text{Ob}( with \Ob(. There are
	still some occurences of \text{Ob} but these are sets, not the
	operator that takes the set of objects of a category.

Started tags infrastructure

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

More neurotic cleaning up

	modified:   algebra.tex
	modified:   algebraic.tex
	modified:   categories.tex
	modified:   coding.tex
	modified:   cohomology.tex
	modified:   constructions.tex
	modified:   conventions.tex
	modified:   etale.tex
	modified:   flat.tex
	modified:   fpqc-descent.tex
	modified:   homology.tex
	modified:   hypercovering.tex
	modified:   injectives.tex
	modified:   introduction.tex
	modified:   modules.tex
	modified:   morphisms.tex
	modified:   properties.tex
	modified:   schemes.tex
	new file:   scripts/parse.py
	modified:   sets.tex
	modified:   sheaves.tex
	modified:   simplicial.tex
	modified:   sites.tex
	modified:   spaces.tex
	modified:   stacks-groupoids.tex
	modified:   stacks.tex
	modified:   topology.tex

More changes to simplicial and homology