backport p2 enhancements: -e, potion_cmd_exec, -D?

add filename to potion_parse, add potion_cmd_exec, add DEBUG_PARSE_VERBOSE,
use dump*?_str,p macros
prepare other compilers (c, exec)
remove verbose (replaced by P->flags |= DEBUG_VERBOSE)
bump POTION_MINOR=1

broke 2 JIT tests: test/closures/long.pn SEGV, test/closures/upvals.pn <>
add test/runtests.sh (potion version only)

usage: test/runtests.sh [test-file]
or     cmd="valgrind ./potion" test/runtests.sh [test-file]