[fix] the exercise the set-up refers to is now called the basics exercise

See merge request !24

[exercise-grids] Add .geo script for the structured grid.

See merge request !18

Feature/biomin readme

See merge request !19

Feature/exercise grids

See merge request !17

Feature/improve fluidsystem ex

Closes dumux#513

See merge request !4

[feature] add exercise main file with readme and solution

See merge request !2

Feature/exercise-runtimeparams

See merge request !15

Cleanup/exercise basic

See merge request !12