Fit Makefile for the Python doc environment better; this is a step toward including the howtos in the build process.
Fit Makefile for the Python doc environment better; this is a step toward
including the howtos in the build process.

	* Put LaTeX output in ../paper-<whatever>/.
	* Put HTML output in ../html/
	* Explain some of the Makefile variables
	* Remove some cruft dating to my environment (e.g. the 'web' target)

This makefile isn't currently invoked by the documentation build process,
so these changes won't destabilize anything.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator