Update home.md

fix (features & colorspaces) links
Update features.md

Fix "Camera calibration with veejay" , "Reloaded", "TwinView / One BigDesktop", "Perspective Transform" links
fix result & start images

fix images : 
* clean double result1.png entries
* add start.png has "Setup screen"
strong emphasis for keystrokes
remove blank list entries
emphasis light & strong

* strong emphasis : keystrokes and cmd
* light emphasis : paths
missing on emphasis
Merge pull request #1 from d-j-a-y/master

Minors updates on few .md files