add initial support for viewing variants in the sdk config tree. refactor some code which initializes sbsv2 contexts. some hacks added for re-loading configurations when the default config is a variant.

<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.2"?>
<plugin>

   <extension-point id="featureUseTracker" name="Feature Usage Tracker" schema="schema/featureUseTracker.exsd"/>

</plugin>