Add empty string support to String.contains?/ends_with?/starts_with?
Add empty string support to String.contains?/ends_with?/starts_with?

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