Update to 7.50.

7.50 2017-10-30

• Deprecated error and finish events in Mojo::IOLoop::Delay. Since there is no good way to warn our users about this deprecation, it will be in effect until the next major release. Where we will also change the base class from Mojo::EventEmitter to Mojo::Base.
• Improved documentation browser with links to MetaCPAN.

7.49 2017-10-28

• Deprecated Mojo::IOLoop::Delay::data and Mojo::IOLoop::Delay::remaining.
• Added Promises/A+ support. Note that Mojo::IOLoop::Delay previously inherited a catch method from Mojo::EventEmitter that was passed the error message as second argument instead of the first, so you might have to change $delay->catch(sub { my ($delay, $error) = @_; ... }); to $delay->catch(sub { my ($error) = @_; ... });
• Added all, catch, finally, race and then methods to Mojo::IOLoop::Delay.
• Updated jQuery to version 3.2.1.