Liblouisutdml Release 2.7.1

This Liblouisutdml release adds a couple of new features and adds support for liblouis 3.9.

For a detailed list of all the changes refer to the list of closed issues.

• New features
• Bug fixes
• Other

New features

• Add support for liblouis 3.9
• Add a Dockerfile
• Add heading supports for opendocument files thanks to Samuel Thibault
• Support automatic page numbering thanks to Samuel Thibault. LibreOffice documents do not provide explicit page numbers, but provides the pagebreak points, so liblouisutdml can simply count the page numbers.
• Move math tables from Liblouis to Liblouisutdml thanks to Bert Frees

Bug fixes

• Use the prefixed LOG_FOO constants thanks to Christian Egli
• Fix cross build from source issue

Other

• Convert the test suite to a standard Automake Parallel Test Harness thanks to Christian Egli
• Set the default log level to LOU_LOG_WARN