Théophile Baquet, left, and Ange Dargent in “Microbe & Gasoline.”Courtesy Screen Media Films “Microbe & Gasoline” bears one of the hallmarks of a Michel Gondry film — a fiercely independent DIY streak — without another of the French director’s more annoying quirks: a self-consciously twee sensibility. Although the semi-autobiographical film centers on a pair of 14-year-old misfits who embark on an unauthorized road trip in a homemade jalopy with a lawn-mower engine disguised as a tiny wooden house, its true theme is not the sometimes overly strenuous oddness of the title characters.