Stable

[danbryce]

BMC heuristic and test domains.

[soonhokong]

@danbryce, I merged them into the dreal/master branch. I've made some changes:

• used --disable-minidebuginfo to configure libunwind to avoid the linker error
• renamed short_sat and bmc_heuristic variables to nra_short_sat and nra_bmc_heuristic. Please note that these changes are only for C++ variables which are for internal uses. dReal still takes --short_sat option instead of --nra_short_sat. I changed the dReach to use --short_sat instead of --nra_short_sat.

I'm running regression tests. Once it's completed, I'll update dreal/stable branch.