migrate concerns into appropriate folders
Fix factories
Implement UID mixin

add mixin/concern for uid
replace users of uid with new mixin

for activity classification, clean up doorkeeper define and add validation on they key attr.
fix dep graph for workbook et al

fixed the dep graph for workbook by adding dependent: destroy and validating presence on important parents (specifically, removing the concept of nil_section).
Switch to schema.rb
Forgery & FactoryGirl instrumentation
work in progress fixes to specs, for serializers etc
more spec fixings-- undoing the access token code mostly
Merge pull request #288 from empirical-org/feature/api-specs

Feature/api specs - complete feature branch merge