Making parameter optional
Add jQuery.ajax test to verify a bug.

The definition does not leverage the returned value of $.ajax()
method well. The official syntax is

```
jqXHR.then(function( data, textStatus, jqXHR ) {}, function( jqXHR, textStatus, errorThrown ) {});
```

(From: http://api.jquery.com/jQuery.ajax/)
Remove tailing space from jquery-test file
Changed .reply definition to allow objects as for body parameter
Add JSDoc for JQueryXHR.abort method.

Inspired the description from its source code:
https://github.com/jquery/jquery/blob/d41e81980ea89e56c04eb14d8c27f4692b367604/src/ajax.js#L487
Write defition for JQueryXHR.then method.

Working on borisyankov/DefinitelyTyped#2314
Add specs for jqXHR object returned by $.ajax

The tests are corresponding to the syntax listed in its website:
http://api.jquery.com/jQuery.ajax/#jqXHR
Adding type definitions for bootstrap-datetimepicker for bootstrap v3
Merge pull request #2317 from bayitajesi/bootstrap-v3-datetimepicker

Adding type definitions for bootstrap-datetimepicker for bootstrap v3
Added support for Google Chrome Notification API

API described at https://developer.chrome.com/extensions/notifications
Merge pull request #2320 from Ch0bits/patch-2

Added support for Google Chrome Notification API
Added Mixpanel definition.
Merge remote-tracking branch 'upstream/master' into AddMixpanel
Add responseJSON attribute to JQueryXHR
Update jquery-tests.ts

Fix spelling...
Update jquery.d.ts

Make responseJSON optional, since it is only present on jqXHR if the Content-Type of the response is "application/json".
Since responseJSON is an "output" parameter on jqXHR, I don't think it makes any functional difference, if it is marked as optional or not, but logically it probably makes more sense...
Merge pull request #2263 from slozier/patch-1

Update SlickGrid.d.ts
Merge pull request #2264 from CyberFoxHax/patch-2

Generics
Merge pull request #2285 from bayitajesi/master

Changes to jquery.dynatree definitions
Merge pull request #2310 from clement911/patch-1

Fix for ix.js groupBy method definition