ellipsis + contexts

`@parser` and `@context`
bridge (config) names and (code) functions.
though the function names must be gotten dynamically (i.e. from strings),
they could be checked statically (i.e. before most code runs).

contexts
`parse.head` gives `parse.body` a context
e.g. the default is prefixing the head if the body starts with an operator
the Parsed tuple tells you how it was parsed

`Parsed` returns name of parser

escape "%" in text for formatting

verbose regex for tokens
e.g. if something looks like a url, don't try to parse the "/" as operators
escape "#"

    ... -> ευ
    tilt head
    calm brow