* Avoid including `lib/*.mal` to prevent unexpected circular
dependencies (bitten by `foldr` using `nth`).
* Ask `quote` before `let*`, the latter requires the former.
Answer previous questions without `let*`.
* Tell the reader that `let*` has various levels of difficulty.
* Drop implicit dependency on `or`, soon out of step files.
* Allow simple recursion in `let*` via a combinator.
Rename the question file for consistency with answer file.
Give an explicit command to copy/paste for tests.
Warn about defining `nth` with `cond`.
Fix typo in let2.
Use tools from core.mal in answers.
It is more interesting to ask an implementation of count from empty?
than the reverse.
Ask for nth, map, concat and conj.
Allow core.mal in answers. Currently, requires the branch with foldr.
Partial translation of examples from lib/ to new tests.
Correct test of memoize.
`reduce`, `foldr`, `every?`, `some` and `and` were previously not
tested in tests/step*.mal. Tests them in `tests/lib/` instead.
- Truncate ruby and python stacktraces since they can get very long
in certain cases causing problems.
- Fix Clojure West example with proper escaping.