shape: rename 'todo' to 'README'
shape experiments: i can use symbols!
shape: update examples
polar example: example with changed spacing
polar shape: change description more
polar shape: change description, add big example
shape: change examples more
polar: even more changes, as suggested by Franek
shape: update README
shape: add pngs
experiments: make simpler
testing polar. works
add slur-attachment function, works nicely but no shorthand suport yet
attach: support multipile shorthands (stem, head, ...)
attach: rewrite code
attach: fishy support for broken slurs
attach: parametrize something
attach: write a nice demonstration
attach: add dedication
shapeII: rewrite. handle arguments inside the procedure for *one* sibling

Previously, we were normalizing the arguments (so that even for one sibling
everything was converted to a list of lists of pairs) and then doing all kinds
of crazy conversions on them.  However, since i'm going to allow even more
special crazy formats, this would become really inconvenient, so i moved all
"conversion" logic to be done separately for each sibling.

This seems to produce much cleaner code.