Added fixpoint search & improved output messages
Added fixpoint search & improved output messages

2-3 iterations of the minimization process is often required to reach a fixpoint. This patch automates the process of finding this fixpoint.

The fixpoint search will repeat the minimization process until `test()` does not succeed at least once during an entire minimization process.

The fixpoint search can be enabled with --fixpoint

esbena/jsdelta,esbena/jsdelta,mtorp/jsdelta,wala/jsdelta,wala/jsdelta,mtorp/jsdelta