Installation Documentation

It´s kind of confusing that there are duplicated installation instructions that differs in some points.

Used the link posted above the RasPi Module does not work, i cloned it and the others from git and got it finally working.

PHP Fatal error:  Class 'EmonLogger' not found in /usr/share/emoncms/www/Modules/user/user_model.php on line 34

https://github.com/Dave-McCraw/pkg-emoncms/blob/master/docs/install.md

Maybe you want  to update the install instructions and/or point to a single page?