Make BibTeX .aux file dependency more precise
Make BibTeX .aux file dependency more precise

Previously, we considered the .aux file a regular input to the bibtex
task, so any change would cause a re-run.  But bibtex actually depends
on very little of the .aux file, and other parts of it do tend to
change, so this was causing needless re-runs of bibtex.  Instead, pull
out and depend on only the lines that matter to BibTeX.

apuignav/latexrun,msullivan/latexrun,mhoogendoorn/latexrun,apuignav/latexrun,FranzSkuffka/latexrun,aclements/latexrun,aclements/latexrun,temporaer/latexrun,mhoogendoorn/latexrun,msullivan/latexrun,temporaer/latexrun,FranzSkuffka/latexrun