Update Examples to Use c++14

[alexbeattie42]

Fixes issue #3929

Brief summary of changes

Update CMakeLists.txt files to use c++14

Testing I've completed

Built examples independently (from an open-sim core installation) and everything compiles and runs.

Looking for feedback on...

None

CHANGELOG.md (choose one)

• updated.

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This change is 

[alexbeattie42]

Updated comments for c++14

[nickbianco]

Just one minor comment about the changelog. I also enabled the CI to make sure that upgrading Tropter to C++14 has no downstream effect on Moco.

[aymanhab]

One follow up question related to this change. Would it be a problem for dependencies if they were built with C++11 flags/settings (e.g. Simbody, and the third party dependencies for Moco) Just wanted to know if this has been assessed. @adamkewley may have performed this assessment since he's been on the forefront of upgrades in the osimCreator project.

[adamkewley]

One follow up question related to this change. Would it be a problem for dependencies if they were built with C++11 flags/settings (e.g. Simbody, and the third party dependencies for Moco) Just wanted to know if this has been assessed. @adamkewley may have performed this assessment since he's been on the forefront of upgrades in the osimCreator project.

It's completely fine. Recommended, even, in the case where the code doesn't need a higher level. OSC's compiling with C++20, OpenSim is C++14, and simbody is C++11. The other dependencies are whatever they are. Haven't had any issues with it via clang, gcc, or MSVC on Linux/Mac/Windows, with/without libASAN, debugging, etc. etc.

[aymanhab]

Awesome, thanks much @adamkewley 👍

[nickbianco]

Per @adamkewley's comment, let's merge. Thanks @alexbeattie42!