Add a PSR-3 compatible logging mechanism in core

Xoops\Core\Logger.php provides a PSR-3 compatible logger. The logger 
creates no direct output, but modules or extensions can register to get 
log messages for further processing. Multiple logging processes can 
register, and each will get the log messages in turn.
Add debugbar module

DebugBar is an error reporting and performance analysis tool. It attaches to the PSR-3 compatible Xoops Logger interface, and feeds into the PHP DebugBar by Maxime Bouroumeau-Fuseau from http://phpdebugbar.com/.
Convert Legacy Logger to the new logging system

Logger is an error reporting and performance analysis tool. It implements the XOOPS legacy logger as an output for the XOOPS PSR-3 logger.
Add monolog module

The monolog module is a logging application that attaches to the PSR-3 compatible Xoops Logger interface. The monolog module feed to logs controlled by Jordi Boggiano's Monolog pacakge: https://github.com/Seldaek/monolog
Incorporate XMF module 1.0 Alpha

The XMF module still exists, but the primary library is moved to xoops_lib
Update composer.json

Adds PSR-0 loading for upcoming Xoops namespace
as well as for Xmf namespace
Adds packages used by new logger, Xmf and some works in progress.
Add composer update instructions to readme