Fix issue #122

[lohedges]

This PR closes #122 by fixing the use of QString::compare when comparing molecular properties. We added a new (as yet unused) is_non_searchable_water property to allow a user to preserve water topologies, e.g. by excluding them from a search. However, I don't want to keep this property when swapping topology, so don't copy it to the new water template. I was incorrectly using QString::compare since I hadn't realised that it returned an int, not a bool. The return value is zero only when the strings match.

This will be tested via BioSimSpace.

• I confirm that I have merged the latest version of devel into this branch before issuing this pull request (e.g. by running git pull origin devel): [y]
• I confirm that I have added a changelog entry to the changelog (we will add a link to this PR as part of the review): [y]
• I confirm that I have permission to release this code under the GPL3 license: [y]

Suggested reviewers:

@chryswoods

[chryswoods]

That is a surprising API - I would have expected compare to return a bool too.

[xiki-tempula]

@chryswoods Do you mind back port this into the main as well, please? Thank you.

[chryswoods]

Yes - although I will delegate ;-)

@lohedges - do you have time to do this tomorrow? I'm at a meeting in London all day.

[lohedges]

Yes, no problem.

[chryswoods]

Thanks :-)

[lohedges]

This is now backported into main.