Feature/add richardsextended test

Closes #421

See merge request !895

Katharina Heck authored 6 years ago and Timo Koch committed 6 years ago

[richards][privarswitch] add basenewtonsolver for richards which derives from privarswitch or normal newtoncontroller

Feature/more generic fluidsystems

Closes #411

See merge request !887

* do some clean-up as well

* add static_assert to make sure one Fluidsystems with one component are used

Feature/results adaptive

See merge request !897

[doc][tutorial] additional in-code comments based on student feedback

See merge request !896

[staggered] Fix linker error

See merge request !901

* the static constexpr dof type indices cannot be stored
  class-wide in gcc5, this lead to linker errors
* store the indices for for each method instead

Feature/component traits

See merge request !899