Simplify application event handling
Rename dependency injection prototype
Stub out initial settings registry and definition
More prototype poking
Add specs for setting definition
Add notification/binding to settings
Update prototypes
Define a hook for binding containers to registries
[settings/definition] Return default when no value given
[settings/registry] alias for definition setters/getters
[settings/registry] Directly pass watched object

The initial watching mechanism was passing around different objects, but
it's a lot simpler to just hand the value we want to bind to a setting.
[settings/register] Remove setting callbacks

There isn't an immediate need for this functionality and it can probably
be implemented in simpler ways.
[settings] Restructure settings classes
Merge branch 'settings-registry'
Bump version for initial rubygems release