Upgrade to jQuery 1.9/2.0

[Christian Boos]

jQuery 1.9 and a beta of 2.0 was recently released: ​http://blog.jquery.com/2013/01/15/jquery-1-9-final-jquery-2-0-beta-migrate-final-released/.

The suggested migration path to jQuery 2.0 is to still make it possible for old IE browsers (< IE9) to be supported thanks to the following "conditionals":

<!--[if lt IE 9]>
    <script src="jquery-1.9.0.js"></script>
<![endif]-->
<!--[if gte IE 9]><!-->
    <script src="jquery-2.0.0.js"></script>
<!--[endif]-->

For the API changes itself, we I think we shouldn't use the migration plugin, but rather aim to adapt our API usage. See the migration guide ​http://jquery.com/upgrade-guide/1.9/:

• .toggle(function, function, … ) removed
• jQuery.browser() removed
• .live() removed
• .die() removed
• jQuery.sub() removed
• .add()
• .addBack( selector ) replaces .andSelf()
• .after(), .before(), and .replaceWith() with disconnected nodes
• .appendTo, .insertBefore, .insertAfter, and .replaceAll
• AJAX events should be attached to document
• Checkbox/radio state in a .trigger()ed "click" event
• Order of triggered "focus" events
• jQuery(htmlString) versus jQuery(selectorString)
• Events not fired by the .data() method; names with periods
• Ordering of disconnected nodes within a jQuery set
• Loading and running scripts inside HTML content
• .attr() versus .prop()
• $("input").attr("type", newValue) in oldIE
• "hover" pseudo-event
• .selector property on jQuery objects
• jQuery.attr()
• jQuery.ajax returning a JSON result of an empty string
• jQuery.proxy() context
• .data("events")
• Removed properties of the Event object
• Undocumented arguments of API methods
• Other undocumented properties and methods

(adding DONE as we go through the list above)