Use auto equatable

Sources/Errors.swift

@@ -37,11 +37,6 @@ public struct TemplateSyntaxError : Error, Equatable, CustomStringConvertible {
   public init(_ description: String) {
     self.init(reason: description)
   }
-
-  public static func ==(lhs:TemplateSyntaxError, rhs:TemplateSyntaxError) -> Bool {
-    return lhs.description == rhs.description && lhs.token == rhs.token && lhs.stackTrace == rhs.stackTrace
-  }
-
 }
 
 extension Error {

Sources/Tokenizer.swift

@@ -114,21 +114,4 @@ public enum Token : Equatable {
       return sourceMap
     }
   }
-
-}
-
-
-public func == (lhs: Token, rhs: Token) -> Bool {
-  switch (lhs, rhs) {
-  case let (.text(lhsValue, lhsAt), .text(rhsValue, rhsAt)):
-    return lhsValue == rhsValue && lhsAt == rhsAt
-  case let (.variable(lhsValue, lhsAt), .variable(rhsValue, rhsAt)):
-    return lhsValue == rhsValue && lhsAt == rhsAt
-  case let (.block(lhsValue, lhsAt), .block(rhsValue, rhsAt)):
-    return lhsValue == rhsValue && lhsAt == rhsAt
-  case let (.comment(lhsValue, lhsAt), .comment(rhsValue, rhsAt)):
-    return lhsValue == rhsValue && lhsAt == rhsAt
-  default:
-    return false
-  }
 }

Sources/Variable.swift

@@ -128,10 +128,6 @@ public struct Variable : Equatable, Resolvable {
   }
 }
 
-public func ==(lhs: Variable, rhs: Variable) -> Bool {
-  return lhs.variable == rhs.variable
-}
-
 /// A structure used to represet range of two integer values expressed as `from...to`.
 /// Values should be numbers (they will be converted to integers).
 /// Rendering this variable produces array from range `from...to`.