Removing cosim::utility::shared_mutex

[ljamt]

• Removing the fiber friendly cosim::utility::shared_mutex
• Also bumping version as this has not been done after 0.8.3 release

[restenb]

Looks good. With the removal of fibers and swap to std::mutex, are there now any changes that are necessary or beneficial to make to cosim::utility::file_lock as well?

I don't think any file operations are currently being done on the thread pool.

[markaren]

Comment talks about fibers

[ljamt]

I don't know what the correct note for lock() should be. Maybe we can use std::lock now?

There are mentions about fibers in almost every doc string in concurrenty.cpp and concurrency.hpp. @kyllingstad, shall we just remove all fiber references in the doc (remove all \pre sections) ?

[kyllingstad]

In most cases, including this one, "fiber" can just be replaced by "thread". But if you want, I can take care of updating the docs in this PR.

[kyllingstad]

I've pushed some doc updates now. I also took the liberty of removing some final traces of fibers in a couple of other places.

[ljamt]

I've pushed some doc updates now. I also took the liberty of removing some final traces of fibers in a couple of other places.

Great! Thanks a lot :)