This new test and emitter update recursively checks the whole source of the

This new test and emitter update recursively checks the whole source of the
latex document for commands that affect what side effect files
will be created, and for graphics files that are included
(so we can convert postscript to pdf if pdflatex is being run).

Now that this is recursive we could tighten up on the side
effect file list (e.g. a \makeindex with no \index commands
won't make all the files we tell scons to expect as side effects)
but I think that is asking for trouble if we mess it up.

git-svn-id: http://scons.tigris.org/svn/scons/trunk@3750 fdb21ef1-2011-0410-befe-b5e4ea1792b1