Change confusing API naming #158

src/ios.js

  * @param  {string} scheme URI scheme that needs to support, optional
  * @return {Promise}
  */
-function openDocument(path:string, scheme:string) {
+function previewDocument(path:string, scheme:string) {
   if(Platform.OS === 'ios')
-    return RNFetchBlob.openDocument('file://' + path, scheme)
+    return RNFetchBlob.previewDocument('file://' + path, scheme)
   else
     return Promise.reject('RNFetchBlob.openDocument only supports IOS.')
 }
  * @param  {string} scheme URI scheme that needs to support, optional
  * @return {Promise}
  */
-function previewDocument(path:string, scheme:string) {
+function openDocument(path:string, scheme:string) {
   if(Platform.OS === 'ios')
-    return RNFetchBlob.previewDocument('file://' + path, scheme)
+    return RNFetchBlob.openDocument('file://' + path, scheme)
   else
     return Promise.reject('RNFetchBlob.previewDocument only supports IOS.')
 }

src/ios/RNFetchBlob/RNFetchBlob.m

     [RNFetchBlobFS slice:src dest:dest start:start end:end encode:@"" resolver:resolve rejecter:reject];
 })
 
-RCT_EXPORT_METHOD(openDocument:(NSString*)uri scheme:(NSString *)scheme resolver:(RCTPromiseResolveBlock)resolve rejecter:(RCTPromiseRejectBlock)reject
+RCT_EXPORT_METHOD(previewDocument:(NSString*)uri scheme:(NSString *)scheme resolver:(RCTPromiseResolveBlock)resolve rejecter:(RCTPromiseRejectBlock)reject
 {
     
     NSURL * url = [[NSURL alloc] initWithString:uri];
 
 # pragma mark - open file with UIDocumentInteractionController and delegate
 
-RCT_EXPORT_METHOD(previewDocument:(NSString*)uri scheme:(NSString *)scheme resolver:(RCTPromiseResolveBlock)resolve rejecter:(RCTPromiseRejectBlock)reject
+RCT_EXPORT_METHOD(openDocument:(NSString*)uri scheme:(NSString *)scheme resolver:(RCTPromiseResolveBlock)resolve rejecter:(RCTPromiseRejectBlock)reject
 {
     
     NSURL * url = [[NSURL alloc] initWithString:uri];