First implementation of the generic CFG analyzer.

It currently drives the Baf and Jimple analyzers.
Target now use F-bounded polymorphism instead of inner types.
Add support for widening/narrowing factories.
Make Parameters do not depend on a target.
Several fixes to comments and initialization.
Small fix.
Improve Scaladoc and ControlFlowGraph api.
Add a SootCFG class to factor out common code of Soot analyzers.
Fix mkString and toString for JVMEnvFixedFrame
Fix PPLProperty for domains without narrowing.
Do not perform unions for nodes with a single incoming edge.
New method to obtain the last program point in Target.
Implement linearDisequality in numerical domains.
Fix addDimension for PPL domains.
Add a new method to add multiple dimensions.
Add utility methods to JVM frames.
Introduce a real test suite for analysis with Soot.