Revert "Add CONTRIBUTION.md. Some correction in README.md. Edit command to install lib."

This reverts commit 76c3d61.

Author: Tim-ats-d

CONTRIBUTING.md

@@ -8,7 +8,7 @@
   <a href="#features">Features</a> •
   <a href="#installation">Installation</a> •
   <a href="#documentation">Documentation</a> •
-  <a href="#quick-start">Quick start</a> •
+  <a href="#quick-start ">Usage</a> •
   <a href="#contributing">Contributing</a> •
   <a href="#license">License</a>
 </p>
@@ -28,10 +28,7 @@
 ## Installation
 
 ### Using pip
-
-```bash
-python3 -m pip install git+git://github.com/Tim-ats-d/Visual-dialog
-```
+`pip install git+git://github.com/Tim-ats-d/Visual-dialog`
 (The lib is not yet available on **pypy**).
 
 ### Requirements