Fixed bug in default Python for correctly stopping if thermally excluded by a direct path & also corrected tunneling possibility check

 - Default Python now correctly stops if it finds that the point is
thermally
   excluded by a direct path when exploring the temperature dependence
of the
   direct-path thermal action.
 - Default Python now also considers tunneling from the false vacuum to
the
   true vacuum at a given temperature impossible if the true vacuum is
now less
   than 0.1 times its length at zero temperature, as a workaround for
PyMinuit
   sometimes not rolling the DSB minimum close enough to the field
origin when
   it should, breaking the unpatched algorithm for deciding if
tunneling is
   still possible.