Added database interface and mock implementation using car factory;
Added three sample cars to the database - Opel Corsa CDTI, Mercedes S
and Ferrari Testarossa
Removed unused classes;
Added user request TO;
Added simple rule to CLIPS that checks the equality of enums;
Merge branch 'master' of https://github.com/efdouk/pricing_engine

Conflicts:
	Pricing_engine/src/softcomputing/task2/carpurchase/model/Car.java