Simplified category create function
Add validation rules to category model
Pass through errors into the edit template
Make comments and errors consistent
Add validations to models and display errors on views
Merge remote-tracking branch 'origin/master' into model_validations

Conflicts:
	app/resources/categories.js
Add flash messages to application
Add an alert area for flash messages in admin template
Save article with category in one action
Add flash messages when article is created successfully
Check session for an article when creating
Check for possible database errors and try to recover from them gracefully, and alerting the operator wherever possible
Fixed some formatting and made warning message consistent
Check for possible errors when creating a category and respond accordingly