cleanup old comments

fix how tag strings are parsed

delete old entrypoint

skip empty tags when building index line

cleanup and adding some docstrings

changed options var name and added check/defaults

changed format of pt index lines and added links

generate separate indexes for tags

some refactoring and cleanup

fix make link error

fix previous fix

fix indented list parsing bug

change fname for _index.md files, and fix links to these

set some option defaults

remove blank lines in header missing fields

added licence and readme

additions to prev commit

small refactoring index processing

added rudimentary html index of pt files

write index to pt dir