Merge pull request #2191 from dennishendriksen/master

Remove doc generators (see model registry docs) + fix pom error
HTML and JS escaping in Freemarker templates
Move HTML escaped chars to freemarker
Update freemarker 2.3.18 --> 2.3.21 (enable json_string)
Merge branch 'master' of https://github.com/molgenis/molgenis