Fixed #1. Do not modify String.prorotype by default.

If `true` is passed to couleurs function, the prototype is modified.
JSDoc comments and fixes.
Call couleurs in different ways.
Updated str param
Updated docs
Removed log file
Updated headers. Link to LICENSE file
Use `str` instead of `String.prototype`
1.1.0
Changelog
Merge pull request #3 from IonicaBizau/1.1.0

1.1.0