Temporary: Suppress rebuild if only version number changes

This commit takes CITATION.bib and VERSION.tex out of the prereqs
for the pdf files.  They still must be regenerated, but this way
pdfs that are otherwise unchanged are not rebuilt by make.

Conflicts:
	Makefile
Rewrite introduction to asymptotic material

Rewrites the introductory L_p material using sentences and paragraphs.
Rewrite convergence in probability material

Revises and streamlines the convergence in probability and WLLN
material.