feat(problems): add use_pretty_numbers function

[justindujardin]

• sets a global that causes rand_number to return pretty coefficients for use in problems (1-12 ints)
• when turned off generate floats and large ints as before.

[codecov]

Codecov Report

Merging #41 into master will increase coverage by 0.37%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #41      +/-   ##
==========================================
+ Coverage   94.48%   94.85%   +0.37%     
==========================================
  Files          68       68              
  Lines        5059     5017      -42     
==========================================
- Hits         4780     4759      -21     
+ Misses        279      258      -21     

Impacted Files	Coverage Δ
libraries/mathy_python/mathy/about.py	100.00% <100.00%> (ø)
libraries/mathy_python/mathy/problems.py	95.18% <100.00%> (+0.10%)	⬆️
...ries/mathy_python/mathy/agents/action_selectors.py	90.24% <0.00%> (-7.32%)	⬇️
libraries/mathy_python/mathy/agents/fragile.py	96.80% <0.00%> (-3.20%)	⬇️
...aries/mathy_python/mathy/envs/gym/mathy_gym_env.py	95.12% <0.00%> (-1.22%)	⬇️
libraries/mathy_python/mathy/cli.py	94.64% <0.00%> (-0.05%)	⬇️
libraries/mathy_python/mathy/env.py	97.07% <0.00%> (+0.04%)	⬆️
libraries/mathy_python/mathy/util.py	93.22% <0.00%> (+0.26%)	⬆️
...es/mathy_python/mathy/agents/policy_value_model.py	83.76% <0.00%> (+0.64%)	⬆️
...ries/mathy_python/mathy/rules/variable_multiply.py	95.40% <0.00%> (+1.14%)	⬆️
... and 3 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 0620439...1e02395. Read the comment docs.

[github-actions]

🎉 This PR is included in version 0.7.11 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀