the environment was using `chapter` for all classes, but on article it needs to be sections

IN typical LaTeX, the `\and` command is used inside `\author` to separate multiple authors, this allows for that.

also makes it significantly easier to use.

fixes missing spaces in `\declarationofauthorship`

merge local branch 'development' into 'origin/development' of ssh://git@lab.it.hs-hannover.de:2222/qxx-tul-u1/latex-template-hsh.git

closes #18

closes #12
closes #13

- add toc to toc
- alias for adding abstract to toc

is long replaced by `\@professor`