Implement checks for all connection rules in chapter 9

[Per Östlund]

We currently only check some of the rules for connections that are listed in chapter 9 in the specification, and some of the checks are not complete. Most of the rules are very hard to implement in the current design of the instantiation though, so the new instantiation should be designed to make it easier to check these rules. This task is to implement checks for all these rules in section 9.1, 9.2, and 9.3 of the specification.