Initial removal of english books from chinese(zh) books list.
Removal decisions were made comparing it with the english(en) books list; itens with the exact same link were removed.
Further removal may need a more careful consideration, since for some reason these book's titles were translated to chinese in the *zh* list.
Added 3 chinese(zh) books.
Berkeley link doesn't require signup
Add french book "Calcul mathématique avec Sage", collectif
Merge pull request #450 from ericguirbal/fr

Add french book "Calcul mathématique avec Sage", collectif
Merge pull request #448 from hiisi13/master

Algorithms - Berkeley link doesn't require signup
Add Explore Flask book (crowdfunded)
Merge pull request #451 from JIghtuse/master

Add Explore Flask book (crowdfunded)
Add a ruby on rails metaprogramming book

Added "Kestrels, Quirky Birds, and Hopeless Egocentricity" under the Ruby on Rails.
Merge pull request #452 from sbagdat/patch-1

Add a ruby on rails metaprogramming book
Added two Tcl books
Merge pull request #453 from tpoindex/patch-1

Added two Tcl books
Added "A Course in Machine Learning"
Merge pull request #454 from bbuyukguzel/master

Added "A Course in Machine Learning"
Add Arduino
Merge pull request #455 from hiseba/patch-1

Adding Arduino
Add a coffeescript book
Merge pull request #456 from sbagdat/patch-1

Add a coffeescript book
Some changes

- Removed "A Course in Machine Learning". There were 2 same links in the
list. One of them kept which is originally belong the author
- Added 1 Android and 2 Powershell books
Merge pull request #457 from bbuyukguzel/master

Some changes
Merge pull request #447 from jgpacker/master

Initial removal of english books from chinese(zh) books list.