normalization: move computeForbiddenSet from fixpoint.cc
tests: remove function calls from sll-impl-*
fa/run_tests: add basic script
tests: change forester tests
tests: add SLLs with tail ptrs
tests: add tree of CSLLs
folding: polish formating
fa/run-tests: decrease sensitivity when measuring time
fa/tests: add SLL with random creation (using ptr to ptr)
fa/tests: add tests used in CAV'13 evaluation
fa/config: make box approximation the default (has better results)