added documentation about new order prover
- new prover for partial and linear orders by Lukas Stevens and Tobias Nipkow
- See NEWS for more context
syntax: glob
*~
*.class
*.jar
*.marks
*.orig
*.rej
*.vsix
.DS_Store
.swp
syntax: regexp
^contrib
^heaps/
^browser_info/
^doc/.*\.pdf
^src/Tools/VSCode/extension/out/
^src/Tools/VSCode/extension/node_modules/
^Admin/jenkins/ci-extras/target/