Convention Tests Polishing

- [x] wireup in CI build script
- [x] descriptive error for "the observable interface is missing"
- [x] descriptive error for "interfaces have different methods"
- [x] descriptive error for "methods do not have same parameter count"
- [x] descriptive error for "methods do not have same parameters"
- [x] descriptive error for "methods do not have correct return value"
- [x] descriptive error for "oh man method overloads are here and i don't know what to do"
- [x] use `Environment.NewLine` because Mono