Fix bug with Globalize::ActiveRecord#attributes

[nickewing]

The current implementation causes attributes to be fetched from globalize's cache instead of the model's attributes. When a value for an attribute is false, then the cache is checked causing a return of nil instead of false. The end result can cause validation errors when inserting records into the database. This patch first checks to see whether the attribute is set on the model. If it is set, the value is returned, otherwise it returns the value from globalize's attribute cache.

Globalize::ActiveRecord#reload is also patched to play nicely with alias_method_chain from other plugins.