added the ability to specify the name for the uidocumentinteractioncontroller for ios (#485)

Author: tmdude9586

ios.js

@@ -28,11 +28,12 @@ function previewDocument(path:string, scheme:string) {
  * Preview a file using UIDocumentInteractionController
  * @param  {string]} path Path of the file to be open.
  * @param  {string} scheme URI scheme that needs to support, optional
+ * @param  {string} name The name of the target file, optional
  * @return {Promise}
  */
-function openDocument(path:string, scheme:string) {
+function openDocument(path:string, scheme:string, name: string) {
   if(Platform.OS === 'ios')
-    return RNFetchBlob.openDocument('file://' + path, scheme)
+    return RNFetchBlob.openDocument('file://' + path, scheme, name)
   else
     return Promise.reject('RNFetchBlob.previewDocument only supports IOS.')
 }

ios/RNFetchBlob/RNFetchBlob.m

@@ -536,13 +536,14 @@ - (NSDictionary *)constantsToExport
 
 # pragma mark - open file with UIDocumentInteractionController and delegate
 
-RCT_EXPORT_METHOD(openDocument:(NSString*)uri scheme:(NSString *)scheme resolver:(RCTPromiseResolveBlock)resolve rejecter:(RCTPromiseRejectBlock)reject)
+RCT_EXPORT_METHOD(openDocument:(NSString*)uri scheme:(NSString *)scheme name:(NSString*)name resolver:(RCTPromiseResolveBlock)resolve rejecter:(RCTPromiseRejectBlock)reject)
 {
     NSString * utf8uri = [uri stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
     NSURL * url = [[NSURL alloc] initWithString:utf8uri];
     // NSURL * url = [[NSURL alloc] initWithString:uri];
     documentController = [UIDocumentInteractionController interactionControllerWithURL:url];
     documentController.delegate = self;
+    documentController.name = name;
 
     if(scheme == nil || [[UIApplication sharedApplication] canOpenURL:[NSURL URLWithString:scheme]]) {
         dispatch_sync(dispatch_get_main_queue(), ^{