* Implement an autoloader
When cleaning up classes for psr2, things got a bit unwieldy, so I implemented a class autoloader.
I created a PSR-0 compliant LibreNMS directory and moved all classes there that made sense.
Implemented LibreNMS\ClassLoader which supports adding manual class mappings
This reduces the file includes needed and only loads classes when needed.
* Add teh autoloader to graph.php
* Add a small bit of docs
Fix incomplete class in includes/discovery/functions.inc.php
Use exceptions for addHost()
Gets rid of silly mixed return and only returns the device_id. Throwing an exception if we run into any issues.
Slightly modifies api add host output again to include device_id
Update addHost() to return either device_id or a string
modify print_error(), print_message() to allow for $quiet variable
Only call addHost() once in addhost.php, if the snmp version isn't set, addHost will cope
Fix up snmp-scan.php and discovery-protocols.inc.php to detect when a device already exists
change in ip_exists() to make it more readable
