Documentation

Documentation
- Propagate explanations from doc.txt to comments in implementation files
Interface
- Consider adding main file for convenience
  - "galore.ss"
  - require/provide all datastructures with canonical prefixes
  - consider whether to change documentation to use prefixed names
  - obviously, still allow users to get at individual modules
- Improve contracts
  - consider storing content-type contracts for polymorphism checking
- New operations
  - insert*, remove* operations
  - insert with "combine" operation
  - table/set crossover functions
    - domain and range of tables (as sets)
    - table difference/intersection with a set
  - reverse-ordered "loop" functions
  - Check Haskell, OCaml, SML, previous Galore, Edison for other operations
Testing
- Double-check code coverage
- Look into automatic tests from previous Galore implementation