Complete warnings/shims for jQuery 1.8 deprecations

[dmethvin]

http://api.jquery.com/category/deprecated/deprecated-1.8/

• Docs in warnings.md for .andSelf() and .size() (Ref Core, Traversing: Add size & andSelf methods #62)
• .load()
• .unload()
• deferred.pipe()

N.B. Since the .load() and .unload() shims are just like .error() the existing code can just be generalized. None of those need to bubble so .triggerHandler() will do the trick.

@gibson042 Now that we're going all Promise/A+ on Deferred should we un-deprecate deferred.pipe to preserve a way to get the old behavior? If so I can open a docs ticket for that tagged for 3.0.

[dmethvin]

As discussed in the meeting today, we're leaving deferred.pipe() deprecated and should warn for it.

[dmethvin]

I'll close once the 3 PRs land