Printer to print local children of imported components

[kerimoyle]

Addresses #590.

Additional to this test, I'd also expect to be able to specify this relationship (equivalence between imported variables) through the API. This isn't possible at the moment?

Also closes #609

[hsorby]

To be clear it is possible to do this at the moment.

[kerimoyle]

So is this a thing? What should I do in the tutorials? Use dummy variables or wait for an overloaded function?

[nickerso]

What should I do in the tutorials? Use dummy variables or wait for an overloaded function?

Either push ahead with the dummy variable method in the tutorial (this works now) or implement the proposed new API for the convenience methods and use them in the tutorials.

Personally, I'm not sure how much of a convenience that these methods would be so I'd continue on the tutorials with the dummy variables.

[kerimoyle]

I'm going to revert the second commit, as discussion about workarounds there has obscured the actual bug ... I'll add the other as a "nice to have maybe" issue on its own.

[kerimoyle]

Wow, this PR went all over the show! In the end the bug was in the Printer, not the Parser as I'd originally thought. This PR has three aspects:

• Fixed the bug in the printer that was missing local children of imported components (src/printer.cpp). This is the main bit!
• Improved the debug printing of the model structure (test_utils.cpp)
• Added tests for printing/parsing of imports, encapsulations, and connections (tests and resources files)

Ready for review please @agarny @hsorby @nickerso

addressed and made changes

[agarny]

This PR seems to be broken now.

[hsorby]

Just minor API change required I think.

[agarny]

Looks good apart from a few minor requests.