Closes #54

Resolve "Summary arcs must be generated between actual-in and return nodes"

Closes #51

See merge request !56

Dynamic initializerDeclaration in ConstructorDeclaration

See merge request !52

* Small regression: only the last field declared in a constructor is included. This is expected, and will be solved with the new object dependencies.
* Integrate ImplicitNode as boolean in GraphNode.
* Updated tests
* Slice now allows the insertion of implicit instructions, but does not output them when generating the AST.
* Removed list of nodes from slice, as the map contains a superset of the information of the list.

* Update tests with better slices.
* GraphNode#addActionsAfterCall uses varargs instead of a set.
* Improved handling of super() and this() calls.
* ImplicitNode is now generic
* Improved interface in JSysCFG to insert new instructions ad-hoc.
* Constructors now have an implicit "return this".
* Removed JSysCFG#getDeclarationClass, ASTUtils has a similar method.
* VariableActions can now store (but don't propagate) a tree of fields acted
  upon.
* VariableActions can now take null as variable, or any possible expression.
* Automatic generation of the actions for fields (USE(a.x) generates USE(a)).
* Conversely, fields now either traverse their scope or declare an action.
* Handling of ThisExpr.
* Better initialization naming for fields.
* Implemented default initialization of fields if none is present.
* InterproceduralActionFinders:
  * Unified the behaviour of #initialValue()
  * Improved generation of actual-in/out for fields.

Caveats:
* InterproceduralActionFinders cannot process VariableActions that don't resolve
  into a ResolvedValueDeclaration. Thus, 'this' must be declared when entering a
  method or constructor declaration.
* Removed type from IO nodes, as it required resolving expressions and was
  unnecessary for the slicer.

* VariableAction stores the real name and the variable may be null.
* VariableVisitor entrypoint must be #startVisit().

Updated variable_pattern_regex to match VariableActions regarding object fields accessed in different ways

Fix github#44 (-i flag misbehaving)

Closes #44

See merge request !54

Replaced by linear lookup.

Fixes #44