Add option WITH_COMPUTED_GOTOS for Python >= 2.7.11
Add option WITH_COMPUTED_GOTOS for Python >= 2.7.11

adrianbroher/python-cmake-buildsystem,jcfr/python-cmake-buildsystem,python-cmake-buildsystem/python-cmake-buildsystem,davidsansome/python-cmake-buildsystem,thewtex/python-cmake-buildsystem,thewtex/python-cmake-buildsystem