Add support for Swift 3.0

Sources/Namespace.swift

@@ -1,4 +1,4 @@
-public class Namespace {
+open class Namespace {
   public typealias TagParser = (TokenParser, Token) throws -> NodeType
 
   var tags = [String: TagParser]()
@@ -9,7 +9,7 @@ public class Namespace {
     registerDefaultFilters()
   }
 
-  private func registerDefaultTags() {
+  fileprivate func registerDefaultTags() {
     registerTag("for", parser: ForNode.parse)
     registerTag("if", parser: IfNode.parse)
     registerTag("ifnot", parser: IfNode.parse_ifnot)
@@ -21,26 +21,26 @@ public class Namespace {
     registerTag("block", parser: BlockNode.parse)
   }
 
-  private func registerDefaultFilters() {
+  fileprivate func registerDefaultFilters() {
     registerFilter("capitalize", filter: capitalise)
     registerFilter("uppercase", filter: uppercase)
     registerFilter("lowercase", filter: lowercase)
   }
 
   /// Registers a new template tag
-  public func registerTag(name: String, parser: TagParser) {
+  open func registerTag(_ name: String, parser: @escaping TagParser) {
     tags[name] = parser
   }
 
   /// Registers a simple template tag with a name and a handler
-  public func registerSimpleTag(name: String, handler: Context throws -> String) {
+  open func registerSimpleTag(_ name: String, handler: @escaping (Context) throws -> String) {
     registerTag(name, parser: { parser, token in
       return SimpleNode(handler: handler)
     })
   }
 
   /// Registers a template filter with the given name
-  public func registerFilter(name: String, filter: Filter) {
+  open func registerFilter(_ name: String, filter: @escaping Filter) {
     filters[name] = filter
   }
 }