Fixes Xcode 6.1 optional inits, fixes unit test error messages

Uses XCTAssertEqual for most of the tests instead of XCTAssert, since XCTAssertEqual produces better error messages for simple equality assertions, namely, it shows what the result actually was, as well as what it was expecting it to be.
Merge pull request #8 from chatspry/xcode-6.1

Fixes Xcode 6.1 optional inits, fixes unit test error messages