Merge pull request #3 from guicho271828/master

modifying the list that it is currently iterating is an undefined behavior.

fixes issue #1

Using walk-directory instead of own-rolled recursion

Removing useless directory

Rewrote the README

Indentation fix

New, cleaner, smaller way.

Rewriting using a better english.

Adding documentation section in the README.

Adding license.

Initial commit.