Theorem proving: Implementing missing "true under certain conditions" case

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@36405 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Adding support for --language=auto (enables automatic detection)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@36406 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e