P.S.: Here are Lassi's commit comments on this
draft:
- Reformat with HTML Tidy
- Remove sample implementation from SRFI document
- Delete bogus claim about unit name starting with
  a digit
- Note that Chicken parses unknown numbers as
  symbols
- Clarify Specification section with subheadings
- Add hex example mixing letters and numbers
- Add RnRS grammar and detailed explanation of
  ambiguous situations