Merge branch 'develop' into feature/better-placeholders

.gitignore

.gitlab-ci.yml

CONTRIBUTING.md

README.md

build.gradle

src/main/java/org/jastadd/relast/compiler/Compiler.java

src/main/resources/.gitignore

src/main/resources/RelASTVersion.properties

src/test/jastadd/relations/Relations.jrag

src/test/jastadd/relations/Relations.relast