Edit README file for project

This commit moves the information about compiling the pdfs earlier in the
pdf.  It also lists additional instructions for compiling them without latexmk
or make and adds more prominant download links.
Rewrite intro to hypothesis testing

Like most of the recent changes, this one rewrites the introduction to the
inference material so that it uses sentences and paragraphs.  The commit also
tweaks some bibtex references.
Rewrite overview of the Likelihood Ratio Test

This commit rewrites the treatment of the LRT, making it a bit more natural.