Changed .bib files in the testing suite so that none of the entries use a '.' in the entry key. This is the first step towards incorporating namelist formatting templates, since we will use a '.' as an accessor.
Minor changes to documentation and tweak to the 'spie_opteng.bst' template.
Several minor changes to the style templates used in tests 5 and 7 in the testing suite.
Added the template_substitution() function into bibulous.py, allowing me to remove redundant code from each of the four subrouties where it is used. This provides a nice consolidation of code.