FIPS compatibility

[fjarri]

Fixes #4

• Fixed some comments in pseudoprimes.rs
• Added LucasCheck::Regular to match what's described in FIPS-186.5 Section B.3.3
• Flattened the logic in lucas_test() to make it easier to understand when the checks are applied
• Simplified test structure in lucas.rs
• Added hazmat::minimum_mr_iterations() with the recommended formula from FIPS
• Added fips_is_prime_with_rng() and fips_is_safe_prime_with_rng()

Is there a better way to organize the FIPS preset? A fips submodule? Or just prefixes/suffixes? Should we provide a corresponding prime-generation function, or just have users rely on sieve_and_find()? Although maybe we should push it to when we're dealing with #62.

[codecov]

Codecov Report

Attention: Patch coverage is 96.04520% with 14 lines in your changes missing coverage. Please review.

Project coverage is 98.71%. Comparing base (2781841) to head (d85c43e).

Files with missing lines	Patch %	Lines
src/presets.rs	91.22%	10 Missing ⚠️
src/hazmat/lucas.rs	97.14%	3 Missing ⚠️
src/hazmat/float.rs	98.70%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #72      +/-   ##
==========================================
- Coverage   99.46%   98.71%   -0.76%     
==========================================
  Files          10       11       +1     
  Lines        1494     1709     +215     
==========================================
+ Hits         1486     1687     +201     
- Misses          8       22      +14     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.