Unsolicited plays never make it to the Steppenwolf stage, even though thousands of scripts get submitted each year. But John Wells’ play did. “In a matter of months, Wells’ play “Men of Tortuga” has gone from “self-addressed return envelope enclosed” to a gripping full production, currently running through Aug. 28 as part of Steppenwolf’s new First Look Repertory festival in the Garage Theatre. There, Wells’ first play sits alongside “The Sparrow Project” by the nationally established author Melanie Marnich and “A Blameless Life” by Joel Drake Johnson, a fairly prominent Chicago scribe known for his warm humanism. Actually, “Men of Tortuga” doesn’t just sit. It blows its companion pieces out of the garage.”