This enables to generate both AStA-style and FS-style (and in theory
other) protocols.
/close #88

ref #7

/close #92

e.g. [todo:who:what]
e.g. [todo;who]

/close #95

/close #80

Categories can be set per protocoltype.
They are specified as another semicolon-separated argument to
[beschluss;…].
Decisions can be search for their category.
/close #53

/close #27

/close #16