Doxygen Mathjax fix and warnings build status

[bilke]

• Fixed Mathjax (formulas)
• Changed Jenkins to mark build as unstable (yellow) when there are new Doxygen warnings

[chleh]

⏩

But what will be the policy for new doxygen warnings? Will they have to be fixed immediately in the respective PR? Or later on in some Documentation-Specific PR? Furthermore, Doxygen warnings cover only part of the documentation. E.g., they don't cover the keyword docu. What will be the procedure for that in the future? I assume this PR was @endJunction's idea... 😄

[endJunction]

At some point (next week) there will be only a dozen doxygen warnings at all, then the "new warning" will be armed properly, i.e. the PR will not pass (or at least report something). (Let's see first, what this "mark unstable" looks like.)

The keywords will be also covered because the prj file references will not be resolved if there is no prj....keyword.md. In the following stages the keyword.md files will be filled with documentation.

[bilke]

I noticed one problem:

A PR creates a new Jenkins job (PR-xxxx) but a new job has no previous builds and therefore the warnings parser cannot find out if there were new warnings introduced.. So this will only popup once the PR is merged into master..

[ogsbot]

OpenGeoSys development has been moved to GitLab.

See this pull request on GitLab.