Testing, examples, a merged plot and a highlighting editor

During the past week Adam continued reviewing literature on reachability analysis of hybrid systems, implemented a couple of new example models (e.g. one from optimal control theory used by Fuller in 1960 to illustrate Zeno behaviour), added generators and property-based tests for the enclosure semantics, developed a merged plot view for the new plotter and added syntax highlighting (based on RSyntaxTextArea) to the Acumen IDE code editor.