Added channel support to Marionette.d.ts

Marionette.d.ts includes definitions for Backbone.Wreqr, but does not support the recommended way of using the Wreqr object as seen here: https://github.com/marionettejs/backbone.marionette/blob/master/docs/marionette.application.md#accessing-the-global-channel

I've added the Channel object, and a definition to the Radio class as well. This is only a means of getting a specific channel through the channel() method, so while it is possible to create an instance of Radio, I've chosen only to include channel() method, and make it static.

This makes it possible to access the instance of a channel with the name 'global' like this (created if not found), as recommended in the above documentation: 
var channel = Backbone.Wreqr.radio.channel('global');
// channel.vent;

Finally, I've made the parameter context of the setHandler method in the Backbone.Wreqr.Handlers class optional, as this adheres to the actual implementation.
Made Wreqr.radio a module
add object path
 Underscore.js: Updated chained calls to first() so that they return a _ChainSingle<T> instead of _Chain<T>. This causes a future call to value() to return a single T rather than an array of T which matches underscore's behavior.
Merge pull request #2541 from Wordenskjold/master

Add channel support to backbone.wreqr in marionette.d.ts
Merge pull request #2586 from bomiller/underscore-chain-first

 Underscore.js: Fix for chained calls to first()
Update CONTRIBUTORS.md
Merge branch 'object-path' of github.com:pocesar/DefinitelyTyped into pocesar-object-path
Merge branch 'pocesar-ot push origin master:object-path'
Added title to
Merge pull request #2587 from johnnyreilly/master

Added title to IRootScopeService
added static html() methods to cheerio
fix .travis.yml from https://github.com/travis-ci/travis-ci/issues/2591
Correct parameter optionality

The last three parameters of ticker.addEventListener are optional. See: http://api.greensock.com/js/com/greensock/TweenMax.html#ticker
Merge pull request #2589 from allentc/master

Correct parameter optionality
Added definition and tests for angular-bootstrap-lightbox. (https://github.com/compact/angular-bootstrap-lightbox)
Update CONTRIBUTORS.md
fix SlickGrid declaration
Merge pull request #2591 from borisyankov/fix-slickgrid

fix SlickGrid declaration
Add loadZoneDataFromObject function.