add sphinx/doc_readme.txt

This file explains how to generate the manual.pdf
copy pdf into main folder after compiling

the default location _build/latex/ is inconvenient...
fix package/module python weirdness

We no longer import constants in __init__ so that it works without
installing.
extract debye test, cleanup
remove unused code from seismic
Merge pull request #51 from tjhei/crazy_init_fixes

Crazy init fixes
Merge pull request #45 from tjhei/add_pdf_readme

Add pdf readme
document constants and avoid scipy for Boltzmann
Merge pull request #52 from tjhei/document_constants

Document constants and avoid scipy for Boltzmann
Test for numba performance improvements
Merge pull request #38 from ian-r-rose/test_numba

Test for numba performance improvements
fix test output
Merge pull request #54 from tjhei/fix_tests

fix test output