* rename `beat` option to `stackBy` to `repeat`
* fix parse error reporting
* rename `weight` to `tactus` (it might in the end be pulse, step, or tap)
* tactus marking with ^
* and add some tests
* annotate pure values with their value, allowing single mininotation values to maintain their labels as pure
* Don't use any 'patternified' arguments if they're all 'pure'
* allow pattern weights (roughly, beats-per-cycle) to be inferred where possible, including from mininotation and across many transformations (e.g. `fast` with a 'pure' factor)
* Add `beatCat`, similar to `timeCat` but funkier
* `silence` has a weight of 1, add alternative `nothing` with a weight of 0, and `gap` function with weight argument
* preserve weight across applicative operations (weight comes with the structure)
* add `stack` alternatives that take advantage of pattern weights to align patterns differently - `stackLeft`, `stackRight`, `stackCentre`, `stackExpand`, with `stackBy` with an argument for patterning the alignment.
fixes#504
* support list syntax in mininotation
* support compound controls
* remove redundant : splitting of s/n and note/n from webaudio
* patternable scale names
