Better debugging levels in Source/wali/graph

PPP_DBG switches debugging on/off in Source/wali/graph/InterGraph.cpp and Source/wali/graph/IntraGraph.cpp.
Added different levels 0/1/2 of verbosity. 0 only prints statistics at the end. 1 addtionally prints out graphs and regexp in dot format. 2 gives arbitrary information that is being used for debugging, no fixed format.
Changed bdd variable order to TENSOR_MIN_AFFINITY

bdd tensor is extremely slow under the earlier order of MATCHED_PAREN. That order was needed for the nwa based detensor. It does not make sense of normal detensor anyway, so going back to TENSOR_MIN_AFFINITY, which is known to be the fastest of all available orders at this point.
Bug fix in PUSH_EVAL option of RegExp evaluation

RegExp::evaluate(sem_elem_t) was implemented incorrectly under PUSH_EVAL. Regexp::value is not enough for the answer, the whole regular expression must be reevaluated, as done without PUSH_EVAL.
HotFix for Newton solver: Less constant terms in equation.

Drop constant terms when linearizing linear terms. I'm not sure this is theoretically even safe to do. I am verifying my answers against the baseline, and haven't found any descripency yet. (against 230 smaller programs from the slam test suit)
Split NewtonCompare::endToEndCompare into two functions.

Split into two functions the part that runs Newton, and that runs Fwpds poststar. This helps profile the two parts independently.