Remove near-duplicated Makefiles and conf.py files

Previously, we had been (sort of) supporting builds of just the User's
Guide or just the Tech Note via near-duplicated copies of the Makefile
and conf.py file. However, these didn't really seem to work right for an
html build (the files ended up in the wrong directory structure), and
this was going to be harder to support and maintain moving forward,
because of the duplication. Erik Kluzek and Keith Oleson have confirmed
that they don't actually need support for an html build of just part of
the documentation. I have made changes to the main Makefile to support
just building a pdf of the tech note (not including the User's Guide),
which IS needed.

Author: billsacks

doc/Makefile

@@ -23,6 +23,19 @@ fetch-images:
 
 .PHONY: help fetch-images Makefile
 
+# For the pdf, we only build the tech note, but use the conf.py file in
+# the top-level source directory (the -c option says where to find
+# conf.py). Note that we also override the setting of
+# numfig_secnum_depth in order to have figure numbering as desired in
+# the pdf, given that the pdf just contains the tech note, so doesn't
+# have the top-level numbering present in the web documentation (where
+# top-level section 1 is the User's Guide and section 2 is the Tech
+# Note).
+#
+# The use of $(0) is as in the catch-all target.
+latexpdf:
+	$(SPHINXBUILD) -M $@ "$(SOURCEDIR)/tech_note" "$(BUILDDIR)" -c "$(SOURCEDIR)" -D numfig_secnum_depth=1 $(SPHINXOPTS) $(O)
+
 # Catch-all target: route all unknown targets to Sphinx using the new
 # "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
 %: Makefile