- Added initial implementations for terms and values
- Error messages converted to pretty printer
- Colorization for error messages
- Color and console width option both as command line and repl command
Sort by proportion of bound variables used, which is likely to get us
the right answer quicker. The results are generated in batches of 16 (a
completely arbitrary choice) then sorted.
Rather than returning a complete list of results, return a pair of the
first result, and a continuation. The continuation explains how to
continue the search if the given result is deemed unacceptable (either
on encountering an error somewhere, or just if the caller wants the next
result).
This means we don't search needlessly if we're only looking for the
first result. Fixes#228
