first cut at a Jahresbericht document class; for now:

• similar to teckids2pubmat (DIN A4, etc.)
• embeds tikz, tikzscale, pgfplots, filecontents
• defaults to CC-BY-SA 3.0 (DE) or later
• new command \teckidsjahresberichthdr{year1}{year2}%

more changes tbd later