Setting language level in IDEA project to JDK7.
Refactoring to use JDK7 diamond type <>.
Further refactorings to use JDK7 syntax.
Merge branch 'master' into refactor-subtype

Conflicts:
	src/org/eclipse/imp/pdb/facts/io/ATermReader.java
	src/org/eclipse/imp/pdb/facts/io/StandardTextReader.java
	src/org/eclipse/imp/pdb/facts/type/ListRelationType.java
	src/org/eclipse/imp/pdb/facts/type/RelationType.java
	src/org/eclipse/imp/pdb/facts/type/TypeFactory.java