provide a file URL when unzipped

https://github.com/marmelroy/Zip/issues/78

Zip/Zip.swift

@@ -82,7 +82,7 @@ public class Zip {
      - notes: Supports implicit progress composition
      */
     
-    public class func unzipFile(_ zipFilePath: URL, destination: URL, overwrite: Bool, password: String?, progress: ((_ progress: Double) -> ())? = nil) throws {
+    public class func unzipFile(_ zipFilePath: URL, destination: URL, overwrite: Bool, password: String?, progress: ((_ progress: Double) -> ())? = nil, fileOutputHandler: ((_ unzippedFile: URL) -> Void)? = nil) throws {
         
         // File manager
         let fileManager = FileManager.default
@@ -218,6 +218,11 @@ public class Zip {
                 progressHandler((currentPosition/totalSize))
             }
             
+            if let fileHandler = fileOutputHandler,
+                let fileUrl = URL(string: fullPath) {
+                fileHandler(fileUrl)
+            }
+            
             progressTracker.completedUnitCount = Int64(currentPosition)
             
         } while (ret == UNZ_OK && ret != UNZ_END_OF_LIST_OF_FILE)