Replaces double quotes on problematic regex strings (mostly ones that have escape sequences that are easier to preserve in single quotes). Necessitates also changing single quotes to `.`, i.e match any.
For some (mostly ones that only have a single escaped character, or were using `\.` to match a literal fullstop) keep the double quotes and fix the regex instead.
Modifies smt2 backend to recognize `$anyconst` etc. assigned to a wire with the `maximize` or `minimize` attribute and emit `; yosys-smt2-maximize` or `; yosys-smt2-minimize` directives as appropriate.
Modifies `backends/smt2/smtbmc.py` and `smtio.py` to recognize those directives and emit a `(maximize ...)` or `(minimize ...)` command at the end of `smt_forall_assert()`, as described in the paper "νZ - An Optimizing SMT Solver" by Nikolaj Bjørner et al.
Adds an example `examples/smtbmc/demo9.v` to show how it can be used.
