Release v1.7.0 not backwards compatible

[bernhard-thiele]

Commit 1b03b84 added a dependency to an MSL icon which was newly introduced in MSL v3.2.3. As a result MDD v1.7.0 unintentionally will not work if used with a previous MSL version. We should probably aim for a bug fix release v1.7.1 which establishes backwards compatibility.

[tbeu]

So basically this means, we only increase the version of the uses annotation (as e4c854a did), to please the Dymola auto-conversion, but must not actually update any library code to utilize new features. Sigh. If we only had impact.

[bernhard-thiele]

Unfortunately, I don't know a better way using the current version handling facilities. This uses(...) annotation should be enhanced, but I suppose that would mean to agree on a common versioning scheme like SemVer and support it in a standardized fashion.

[bernhard-thiele]

I've made a draft release for v1.7.1 and planned to publish it this Friday, 2019-04-05. This can be moved to a later date if there pop up some other issues which should be solved.