Clang: introduce more data in TokenInfo

Data added:
- return type spelling for functions
- parent spelling
- access specifier for class fields and methods
- storage class

New highlighting types are added, therefore
types are now categorized by class, struct, etc.

Change-Id: I1739b94a6f777045fde655060d8b9a12b6e0889b
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

tests/unit/unittest/data/cursor.cpp

@@ -127,3 +127,11 @@ void PointerToConst(const int *);
 void Pointer(int *);
 void ConstantPointer(int *const);
 void ConstIntegerValue(const int);
+
+void NonFinalStruct::ProtectedMethodAccessSpecifier() {}
+
+extern int ExternVarStorageClass;
+
+static void StaticMethodStorageClass() {}
+
+template<class T> const T &InvalidStorageClass(const T &type) { return type; }