This relaxes the previous requirement that cancan has to be loaded before any models are. append_extensions will apply to all previously loaded models as well as ones loaded after.
…ataMapper - closes #373
…isn't found - closes #366
1) remove all empty conditions hashes from the rules, they are included in the records through `@model_class.all` 2) only process can rules if the new and old rules lists are the same length (meaning there were no empty conditions hashes) 3) always process cannot rules
* adds mongoid query that matches every record when rule.conditions.empty? is true