Fixed most used tag retrieving
Fixed assert error message; added new method
Fixed automatic featuring post

- Fixed main page view
- Code moved from StaticPagesController to PostModel
- Code split into semantically meaningful methods
- Allowed anonymous featuring through API
- Added protection against automatic featuring of hidden post
Changed job arguments convention back

Restored JobArgs approach. Previous introduction of hierarchic argument
definitions has backfired: it was confusing what class to take arguments
from, the concept of sharing arguments between different jobs was
unintelligible and one never knew where given argument was actually
defined.

This appraoch makes it easier to maintain the arguments list and
simplifies the code a lot.
Fixed mass tag redirect
Removed unused method
Removed unused classes
Fixed post safety user settings
Added argument checking system
Increased API readability

- Removed Abstract*Job hierarchy
- Introduced EntityRetrievers
- Introduced JobPager
- Moved files around
Fixed mass tag and tag renaming
Fixed tag renaming
Fixed entity retrievers
Added protection against 2 users having same mail
Fixed password reminder
Fixed canEditAnything method in EditUserJob
Fixed confirming user registration by staff
Moved setRelationsFromText logic to controller
Fixed exception throw in UserModel
Modified post path management