Add unit testing bundle
HOTPGeneratorTests
Remove unused AuthenticatorTests.m
TOTPGeneratorTests
Legacy OTPAuthURLTest
Merge branch 'tests'
Silence warnings in OTPAuthURLTest
Enable Clang modules
Silence module warnings (-Wauto-import) in library headers
Silence gnu warnings in the test bundle, since XCT assertions throw dozens of them.
Remove target-specific warning flags already enabled in Common.xcconfig
Cleaned up build settings by making some target settings common to the project and removing others which were unnecessary
Merge branch 'warnings'