Non-breaking internal restructuring

[mikeingold]

Completed

• Major internal re-stucturing and re-organization
  • Moved IntegrationAlgorithms from integrals.jl to a new file
  • Consolidated all non-specialized _integral workers into integrals.jl
  • Moved specialized geometry-specific methods from integral_*.jl files into geometry-specific files under the new /src/specializations/ directory
  • Made _integral the first-line worker for all integrals; the only remaining _integral_Nd methods are subordinate to _integral(f, ::GaussKronrod) methods
  • Culled some obsoleted and redundant method definitions
• Generalized GaussLegendre integrals to a single n-dimensional method
• Allow differential and jacobian to accept argument ts as a Tuple
• Marginally loosened a few test tolerances (rtol=1e-6) to mitigate occasional test failures
• Bump package version from v0.13.4 to v0.13.5 and remove sole author credit

Note on test coverage: the Ring, Rope, and BezierCurve methods identified as lacking coverage already existed and were only moved to new files in this branch. Ordinarily I would use this opportunity to define tests for them, but the affected methods are going to be obsoleted in an upcoming PR that converts FP to a keyword argument.

Future Work

• Convert FP to a keyword argument.
  • Figure out how to ensure clean pass-through of arguments from alias functions, e.g. lineintegral -> integral -> _integral?
• Rename IntegrationAlgorithm to IntegrationRule, change references from "algorithm", "settings", etc to "rule"
• Add "Why Specialized" lines to each specialization source file: why does this geometry require specialized methods vs the generalized ones?

[codecov]

Codecov Report

Attention: Patch coverage is 93.19372% with 13 lines in your changes missing coverage. Please review.

Project coverage is 90.35%. Comparing base (7674006) to head (1e997a4).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/specializations/Ring.jl	50.00%	4 Missing ⚠️
src/specializations/Rope.jl	50.00%	4 Missing ⚠️
src/integral.jl	86.95%	3 Missing ⚠️
src/specializations/BezierCurve.jl	90.90%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #79      +/-   ##
==========================================
- Coverage   90.93%   90.35%   -0.59%     
==========================================
  Files           7       16       +9     
  Lines         353      311      -42     
==========================================
- Hits          321      281      -40     
+ Misses         32       30       -2     

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

[mikeingold]

@JoshuaLampert Just a heads-up: I was planning for this branch/PR to become a major version bump, but the first (non-breaking) half of the job wound up being so extensive that I think I'm going to split those plans into two PR's. This reorganization is mostly moving methods into different files, combining some redundant wrapper methods, and implementing a generalized Gauss-Legendre method. I'll need to look over everything again, but it should probably be ready for review in the next day or two.

[JoshuaLampert]

Nice! I like having more structure in the code. I didn't check everything in detail (especially I assume the copy/paste is fine). I just left some minor comments and questions below.