Convert Algorithm case names to lowercase, following Swift 3 conventions

[mattrubin]

While not made explicitly clear in the API design guidelines, in the Foundation Swift 3 API even names with are acronyms are lower-camel-case.

https://swift.org/documentation/api-design-guidelines/#follow-case-conventions

[codecov-io]

Codecov Report

Merging #123 into develop will not impact coverage.

@@           Coverage Diff            @@
##           develop     #123   +/-   ##
========================================
  Coverage    94.73%   94.73%           
========================================
  Files            6        6           
  Lines          380      380           
========================================
  Hits           360      360           
  Misses          20       20

Impacted Files	Coverage Δ
Sources/Generator.swift	100% <ø> (ø)	✅
Sources/Crypto.swift	100% <100%> (ø)	✅
Sources/Token+URL.swift	98.38% <100%> (ø)	✅

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