Conform to ExpressibleByArrayLiteral and ExpressibleByDictionaryLiteral

[fwcd]

Fixes #48

This branch adds experimental support for the aforementioned protocols.

[stephencelis]

@fwcd Check out how we implemented it in swift-tagged: https://github.com/pointfreeco/swift-tagged/blob/f3f773a5e13f3c8f0ab1ce2ae6378058acefa87d/Sources/Tagged/Tagged.swift#L289-L314

I think you could do similar here to conditionally support any underlying collection that conforms to the ExpressibleBy* protocol.

[fwcd]

That's a neat workaround to the issue that Swift doesn't have a spread operator yet and definitely the simpler solution.

Unfortunately, there is another issue, certain overloads now become ambigous with [3, 4, 5] being interpretable as both an array and a NonEmpty:

.../git/swift-nonempty/Tests/NonEmptyTests/NonEmptyTests.swift:124:20: error: ambiguous use of 'isDisjoint(with:)'
    XCTAssertFalse(NonEmptySet(1, 2, 3).isDisjoint(with: [3, 4, 5]))
                   ^
.../git/swift-nonempty/Sources/NonEmpty/NonEmpty+SetAlgebra.swift:75:15: note: found this candidate
  public func isDisjoint(with other: NonEmpty) -> Bool {
              ^
.../git/swift-nonempty/Sources/NonEmpty/NonEmpty+SetAlgebra.swift:79:15: note: found this candidate
  public func isDisjoint(with other: Collection) -> Bool {
              ^

[stephencelis]

Unfortunately, there is another issue, certain overloads now become ambigous with [3, 4, 5] being interpretable as both an array and a NonEmpty:

Hm! Could you try adding a @_disfavoredOverload annotation to the one that takes a NonEmpty?

[fwcd]

That did the trick, thanks! The test suite now passes.

[stephencelis]

Awesome! Thanks for taking the time to contribute 😄