Explain differences between tutorial and this implementation

Tutorial was written for PDELab, so it has functions spaces etc.

Depends: #13 (closed), so there is less to explain

marked this issue as related to #12 (closed)

marked this issue as related to #13 (closed)

changed the description

mentioned in merge request !21 (merged)

mentioned in commit 0f11eb00

closed via merge request !21 (merged)