* Fix Python code
* Add the pythontutor blocks of the chapter tree, heap, graph, searching, sorting, divide and conquer, dynamic programming and greedy.
Improve the pythontutor blocks of the chapter array and linkedlist and backtracking.
Add the tutorial of pythontutor in how-to-read section.
* Reduce the image's file size.
* Update all the figures
* Update the data structure, sorting, divide and conquer chapters' covers. Add the English edition covers.
* Fix the link of EN translation in README
* Update README.md
* Update README.md
* Update README-en.md
* Sync recent changes to the revised Word.
* Revised the preface chapter
* Revised the introduction chapter
* Revised the computation complexity chapter
* Revised the chapter data structure
* Revised the chapter array and linked list
* Revised the chapter stack and queue
* Revised the chapter hashing
* Revised the chapter tree
* Revised the chapter heap
* Revised the chapter graph
* Revised the chapter searching
* Reivised the sorting chapter
* Revised the divide and conquer chapter
* Revised the chapter backtacking
* Revised the DP chapter
* Revised the greedy chapter
* Revised the appendix chapter
* Revised the preface chapter doubly
* Revised the figures
