Update SUMMARY.md

Author: KevinHM

SUMMARY.md

@@ -3,37 +3,37 @@
 * [introduction](README.md)
 * [致谢](chapter1/acknowledagements.md)
 * [理念](chapter2/philosophy.md)
-   * [函数响应式编程](chapter2/functional_reactive_programming.md)
-   * [结论](chapter2/conclusion.md)
+ * [函数响应式编程](chapter2/functional_reactive_programming.md)
+ * [结论](chapter2/conclusion.md)
 * [用RXCollections进行函数式编程](chapter3/functional_programming_with_RXCollections.md)
-  * [高阶函数](chapter3/Higher_Order_Functions.md)
-  * [使用RXCollections](chapter3/installing_RXCollections.md)
-  * [映射](chapter3/map.md)
-  * [过滤](chapter3/filter.md)
-  * [折叠](chapter3/fold,md)
-  * [性能](chapter3/performance.md)
-  * [总结](chapter3/conclusion.md)
+ * [高阶函数](chapter3/Higher_Order_Functions.md)
+ * [使用RXCollections](chapter3/installing_RXCollections.md)
+ * [映射](chapter3/map.md)
+ * [过滤](chapter3/filter.md)
+ * [折叠](chapter3/fold,md)
+ * [性能](chapter3/performance.md)
+ * [总结](chapter3/conclusion.md)
 * [ReactiveCocoa 简介](chapter4/introduction_to_reactivecocoa.md)
-   * [使用ReactiveCocoa](chapter4/installing_reactivecocoa.md)
-   * [流和序列](chapter4/streams_and_sequences.md)
-   * [信号](chapter4/signals.md)
-   * [订阅](chapter4/subscriptions.md)
-   * [状态推导](chapter4/deriving_state.md)
-   * [指令](chapter4/commands.md)
-   * [RACSubject](chapter4/racsubject.md)
-   * [热信号与冷信号](chapter4/hot_and_cold_signals.md)
-   * [组播](chapter4/multicasting.md)
-   * [总结](chapter4/conclusion.md)
+ * [使用ReactiveCocoa](chapter4/installing_reactivecocoa.md)
+ * [流和序列](chapter4/streams_and_sequences.md)
+ * [信号](chapter4/signals.md)
+ * [订阅](chapter4/subscriptions.md)
+ * [状态推导](chapter4/deriving_state.md)
+ * [指令](chapter4/commands.md)
+ * [RACSubject](chapter4/racsubject.md)
+ * [热信号与冷信号](chapter4/hot_and_cold_signals.md)
+ * [组播](chapter4/multicasting.md)
+ * [总结](chapter4/conclusion.md)
 * [ReactiveCocoa的实践](chapter4/reactivecocoa_practice.md)
-  * [FunctionalReactivePixels的基础知识](chapter4/basic_of_functionalReactivePixels.md)
-  * [添加FunctionalReactivePixels](chapter4/adding_to_functionalReactivePixels.md)
-  * [和FunctionalReactivePixels一起实践](chapter4/revisiting_functionalReactivePixels.md)
-  * [网络层回访](chapter4/networking_layer_revisited.md)
-  * [总结](chapter4/conclusion.md)
+ * [FunctionalReactivePixels的基础知识](chapter4/basic_of_functionalReactivePixels.md)
+ * [添加FunctionalReactivePixels](chapter4/adding_to_functionalReactivePixels.md)
+ * [和FunctionalReactivePixels一起实践](chapter4/revisiting_functionalReactivePixels.md)
+ * [网络层回访](chapter4/networking_layer_revisited.md)
+ * [总结](chapter4/conclusion.md)
 
 * [MVVM On iOS](chapter5/mvvm_on_ios.md)
-  * [什么是MVVM](chapter5/what_is_mvvm.md)
-  * [跟随FunctionalReactivePixels的脚步](chapter5/revisiting_functionalReactivePixels.md)
-  * [MVVM的具体实践](chapter5/mvvm_in_practice.md)
-  * [测试ViewModels](chapter5/testing_viewModels.md)
-  * [终稿](chapter5/final_thoughts.md)
+ * [什么是MVVM](chapter5/what_is_mvvm.md)
+ * [跟随FunctionalReactivePixels的脚步](chapter5/revisiting_functionalReactivePixels.md)
+ * [MVVM的具体实践](chapter5/mvvm_in_practice.md)
+ * [测试ViewModels](chapter5/testing_viewModels.md)
+ * [终稿](chapter5/final_thoughts.md)