Handle exit messages from tests in ex_unit
Handle exit messages from tests in ex_unit

Fixes #982

elixir-lang/elixir,antipax/elixir,beedub/elixir,pedrosnk/elixir,lexmag/elixir,kimshrier/elixir,gfvcastro/elixir,pedrosnk/elixir,ggcampinho/elixir,gfvcastro/elixir,ggcampinho/elixir,kelvinst/elixir,antipax/elixir,michalmuskala/elixir,joshprice/elixir,beedub/elixir,lexmag/elixir,kimshrier/elixir,kelvinst/elixir