Add implementation of simple Registry (removing Zend_* dependency)
Removing all uses of Zend_Registry from core/ plugins/ and tests/
Merge branch 'master' into registry

Conflicts:
	core/ErrorHandler.php
	core/ExceptionHandler.php
	core/FrontController.php
	core/Log.php
	core/Piwik.php
Comitting falsely excluded schema file
Add another falsely excluded file
Merge branch 'master' into registry
Update FrontController.php
Fix failing tests by throwing Exception when accessing unset value.
Merge branch 'registry' of https://github.com/piwik/piwik into registry
Merge pull request #111 from piwik/registry

Removing Zend_Registry from Core

fixes #4188