Added output node to method declaration + changed return to output

[jacosro]

Changes

• Renamed NodeType: METHOD_CALL_RETURN -> METHOD_OUTPUT
• In each method declaration, an output node is added, and a return arc is added from every node with a ReturnStmt to it
• Renamed return node to output

[jacosro]

New changes:

• Restored METHOD_CALL_RETURN node type and assigned to output node of the method call
• Added addDataDependencyArc method in SDG class to add a data dependency arc with no information about the variable
• When creating output node of the call, check first if method return type is void
• Removed ReturnArc
• Arcs former ReturnArcs are now as follows:
  • ReturnStmt nodes -> output node (inside method declaration) [DataDependencyArc]
  • output node (inside method declaration) -> output node (method call) [ParameterInOutArc]
  • output node (method call) -> method call node [DataDependencyArc]