Convert general settings page to ember data

Issue #2846
-Implement custom RESTAdapter and serializer for settings data.
-Convert theme selector to Ember.Select.
-Finish upload modal and wire into settings page.
Add Validations Layer and Post Validations

closes #2893, issue #2850, issue #2856
- this is a stable, but quick and dirty validations layer for the time constraints
- this could be replaced with a unified server/client layer later. the infrastructure is there.
- create a validation engine mixin to match validators with models
- override the save method in the mixin to perform validations first
- create a post validator
- fixup calls to .save() to make sure they catch errors properly
Merge pull request #3003 from jaswilli/issue-2846-settings

Convert general settings page to ember data
Merge pull request #3011 from darvelo/validations

Add Validations Layer and Post Validations
Removing unneeded file