Introduce 2 options:
1. BANDIT_BUILD_SPECS to allow Bandit specs to be built. Default is ON.
2. BANDIT_RUN_SPECS to allow Bandit specs to be run. Default is ON. This is dependent on BANDIT_BUILD_SPECS.

Ensure SNOWHOUSE_IS_CPP11 is set to ON.
Point to snowhouse cxx11 branch
Merge pull request #44 from andystanton/feature/add-options

Make bandit specs optional