The test suite requires EV.pm to be present, added it to dist.ini's

TestRequires section. Currently, when I'm installing Promises via cpanm, I get

 # Failed test 'use Promises::Deferred::EV;'
 # at t/052-exceptions-ev-anyevent.t line 12.
 # Tried to use 'Promises::Deferred::EV'.
 # Error: Can't locate EV.pm in @INC (you may need to install the EV module) (@INC contains: t/lib    /home/mschilli/.cpanm/work/1413273423.4595/Promises-0.93/blib/lib /home/mschilli/.cpanm/work/1413273423.4595/Promises-0.93/blib/arch /h

Thanks for this great module!