add Google C++ and Python courses
format free-courses-en.md
Merge pull request #932 from esparta/master

[es] Adding SQL books
Merge remote-tracking branch 'upstream/master'
Update free-programming-books.md

* [Algorithms and Automatic Computing Machines (1963)] (https://archive.org/details/Algorithms_And_Automatic_Computing_Machines) - B. A. Trakhtenbrot
Merge pull request #933 from gchiam/master

[en] add Google C++ and Python courses
Merge pull request #934 from Erendis/patch-2

Update free-programming-books.md
Add 'Rust By Example' to Rust section
Merge pull request #936 from invictusjs/master

Add 'Rust By Example' to Rust section
Added two C++ tutorials.
Alphabetized C++ Section.
Merge pull request #937 from Yohanna/C++-Tutorial

Added two C++ tutorials.
Remove a non-free book
Remove dead link
adding language LUA
fix md books Lua
Merge pull request #938 from viniciusmo/master

Adding Lua pt_BR
Add Think OS book (greenteapress)
Merge pull request #939 from JIghtuse/master

Add Think OS book (greenteapress)
add book "Programming in Martin-Löf's Type Theory" by Bengt Nordström