Iron Man 2 is due in the­atres in two months, and this new trailer makes me appre­ci­ate the work that Jon Favreau has put into this fran­chise. Of course the big sell is the onscreen debut of War Machine — now played by Don Chea­dle, who replaced Ter­rence Howard.  We can’t for­get  the Black Widow as well, who looks like she will make things...