Bugfix:
Only consider the latest versions of each installed gem when finding files to load for .load_all.
Add a name attribute to plugins for introspection.
Add plugin exclusion patterns
Fix loading of grandchildren of plugins
Rename Pluggability::FactoryError to Pluggability::PluginError (with backward-compatibility aliases)
Add loading via underbarred name variants (CommaDelimitedThing -> comma_delimited)
Rename some stuff for consistency.
Simplify Pluggability#derivatives.
First release after renaming from PluginFactory.