Create basic Plugin and Activation models.
Merge branch 'develop' into feature/plugins
Barebone powerup implementations.
Proper name for powerups
Change powerup model locations to facilitate loading.
Suppress unchecked cast warnings. This should be taken care of in the database.
Change return type to correct value.
Create basic untested, but presumably functional DescriptionPowerup.
Change return type as per 5d74d94b...
Merge branch 'feature/plugins' into develop

Conflicts:
	app/controllers/Application.java
	app/models/Club.java
	conf/evolutions/default/1.sql