Swift 5.4 support

Merge pull request #10 from Danappelxx/swift-5.4

Swift 5.4 + spec updates

Cleaner API for Template Collections

There is now only a single directory parameter rather than base path and subdirectory parameters.

Template Collections!

Documentation for template collections can be found in the README.

Swift 3.0, Zewo 0.14 support

Update to Swift 3.0, Zewo 0.14 (#5)

* Update to Swift 3.0, Zewo 0.14
* Update .travis.yml
* Fix test layout