v1.0.4: Allow hyphenated property names in $.style()

Changelog:

• $.Class() now accepts an existing class as the first argument. Useful for augmenting existing classes.
• $.Hooks#add() now accepts an object literal with multiple hooks
• $.style() now accepts hyphenated property names (e.g. background-color as well as backgroundColor), to allow usage for setting CSS Variables, which have no camelCase version.