Introducing new REST feature in Bennu Core foundations
Improved some minor integration issues on REST serializer/deserializers
Remove delegates
Merge branch 'feature-rest' of github.com:pedrosan7os/bennu into feature-rest

Conflicts:
	bennu-core/src/main/java/pt/ist/bennu/bennu/core/rest/AbstractResource.java
	bennu-core/src/main/java/pt/ist/bennu/bennu/core/rest/mapper/AbstractJsonSerializer.java
Code format
Code Format
Merge branch 'feature-rest' into develop

Conflicts:
	bennu-core/src/main/java/pt/ist/bennu/core/domain/groups/DifferenceGroup.java
	bennu-core/src/main/java/pt/ist/bennu/core/domain/groups/IntersectionGroup.java
	bennu-core/src/main/java/pt/ist/bennu/core/domain/groups/NegationGroup.java
	bennu-core/src/main/java/pt/ist/bennu/core/domain/groups/PersistentGroup.java
	bennu-core/src/main/java/pt/ist/bennu/core/domain/groups/UnionGroup.java
	bennu-core/src/main/java/pt/ist/bennu/core/domain/groups/UserGroup.java
	bennu-core/src/main/java/pt/ist/bennu/core/servlets/BennuCoreContextListener.java
	bennu-core/src/main/java/pt/ist/bennu/core/util/ConfigurationManager.java