#152 CRASHES due to memory limits

[Michele Gubian]

we are getting crashes with the following error:
.....terminate called after throwing an instance of 'std::bad_alloc'
what(): std::bad_alloc

a simple way to reproduce is running a talk like id or ldt on a large stimulus set. The one I tried stopped at around 2600 words, I was trying to read the entire SCM CELEX vocab..