Fixed an issue where document generation failed because some OSs are not tolerant of having multiple installed versions of PostgreSQL. A separate VM is now created for each version. Also added a sleep after database starts during document generation to ensure the database is running before the next command runs.
Reported by John Harvey.
1) Started on a general markdown renderer
2) Internal links now work in PDF
3) Improvements to PDF styling
4) Some comment and formatting fixes
5) User guide edits.
