move stronger rules into exercise

added a function that carries out all the reconstruction steps, for improved usability; added documentation;

reconstruction framework for LEO-II's TPTP proofs;

made list of test files a parameter to timed_test in TPTP_Test.thy, and updated dependent definitions;

cleaned code used to produce a proof-graph;

improved configurability of DOT exporter; tuned;

behaviour of tptp_graph now depends on an envir variable to indicate whether to produce proof graph containing formulas or not; tuned;

experimented with presentation of DOT+LaTeX;

edges are now being shown in the proof graph; removed the shapes related to the conjecture and the negated conjecture, to remove clutter (since i'm also showing the inference's conclusion in latex);

added case for handling 'assumption' lines in Satallax proofs;