added some relation tests and fixed some stuff

...primitives/src/main/rust_embedded/btypes/src/brelation.rs

...es_primitives/src/main/rust_embedded/btypes/src/btuple.rs

btypes_primitives/src/main/rust_embedded/btypes/src/lib.rs

...n/resources/de/hhu/stups/codegenerator/RustTemplate_e.stg

...e/hhu/stups/codegenerator/rust_embedded/TestRelation.java

src/test/resources/de/hhu/stups/codegenerator/Closure.mch

src/test/resources/de/hhu/stups/codegenerator/Closure1.mch

...test/resources/de/hhu/stups/codegenerator/Composition.mch

...st/resources/de/hhu/stups/codegenerator/DirectProduct.mch

src/test/resources/de/hhu/stups/codegenerator/Domain.mch

...esources/de/hhu/stups/codegenerator/DomainRestriction.mch

...sources/de/hhu/stups/codegenerator/DomainSubstraction.mch

...sources/de/hhu/stups/codegenerator/DomainSubstraction.out

src/test/resources/de/hhu/stups/codegenerator/Fnc.mch

src/test/resources/de/hhu/stups/codegenerator/Id.mch

src/test/resources/de/hhu/stups/codegenerator/Inverse.mch

src/test/resources/de/hhu/stups/codegenerator/Iterate.mch

src/test/resources/de/hhu/stups/codegenerator/Override.mch

...esources/de/hhu/stups/codegenerator/OverrideAddition.strs

src/test/resources/de/hhu/stups/codegenerator/Range.mch