Merge pull request #298 from esparta/master

3 more spanish books (mostly translations from english books)
add Backbone.js API Link
Some spanish books about javacript and css
Add item(free-programming-books-ko.md)
Added COBOL section with 2 PDFs
Fixed COBOL case
Markdown links need to be lowercase

[COBOL] (#cobol)  works but [COBOL] (#COBOL) doesn't
Merge pull request #299 from minsOne/master

add Backbone.js API Link, README Item
Merge pull request #300 from rodacato/master

Some spanish books about javacript and css
Merge pull request #301 from JoePlant/master

Added COBOL section with 2 PDFs
Lisp pdf link
Merge pull request #302 from OpenCode/patch-4

Lisp pdf link
Creating AngularJS sub-section

Moved "AngularJS in 60 Minutes" to new sub-section Angular.js
js game
Merge pull request #305 from sillero/master

Creating AngularJS sub-section
Added Introduction to Data Science and A First Course in Linear Algebra

Added complete titles as part of 'The Architecture of Open Source Applications'.  
Moved entry to be with 'The Performance of Open Source Applications' which is in the same series.
Merge pull request #306 from lluang/master

Added Introduction to Data Science and A First Course in Linear Algebra
Added Network Science book to Theoretical Computer Science section

I'm not sure exactly what section this belongs in; it seems to be influenced by several fields.  If someone else knows a better section, I'd be happy to move it.
Added books to Datamining and Machine Learning sections
Added several books to Mathematics and one to R

Added 6 statistics books to Mathematics section and one book to the R section