testHelper: reload scripts via AJAX in reloadLib.

jQuery core has introduced code whereby a script (tag) once executed will not be executed again when re-encountered. Thus, appending script tags to the end of the body will no longer have the effect of getting those scripts re-executed. We need to re-run them using $.ajax().
Table: Re-scoped hack for IE9/WP7.5 reflow styles to avoid them applying to other tables types.
Clean up dynamic-samples/category.php. Fixes #5314.

Fixes there errors:

PHP Notice:  Use of undefined constant vehicles - assumed 'vehicles' in ./docs/pages/dynamic-samples/category.php on line 53

PHP Notice:  Use of undefined constant name - assumed 'name' in ./docs/pages/dynamic-samples/category.php on line 54

PHP Notice:  Use of undefined constant description - assumed 'description' in ./docs/pages/dynamic-samples/category.php on line 55

PHP Notice:  Use of undefined constant items - assumed 'items' in ./docs/pages/dynamic-samples/category.php on line 56

PHP Notice:  Use of undefined constant name - assumed 'name' in ./docs/pages/dynamic-samples/category.php on line 58

PHP Notice:  Use of undefined constant name - assumed 'name' in ./docs/pages/dynamic-samples/category.php on line 61

PHP Notice:  Use of undefined constant name - assumed 'name' in ./docs/pages/dynamic-samples/category.php on line 64

PHP Notice:  Undefined index: id in ./docs/pages/dynamic-samples/category.php on line 74

PHP Notice:  Undefined index:  in ./docs/pages/dynamic-samples/category.php on line 82

PHP Notice:  Undefined index: HTTP_X_REQUESTED_WITH in ./docs/pages/dynamic-samples/category.php on line 88

Also added charset in Content-Type header and used json_encode
instead of homebrew unescaped json encoder.

Follows-up cac203291eb9294a2be3f69ce0d5ae954e3a069d
Merge pull request #5315 from Krinkle/php-errors

Issue #5314 - Clean up dynamic-samples/category.php. Thanks @krinkle
Tables: Re-vamped the IE9 CSS hacks to be max-width media queries

This was needed because negating the float and width properties were
causing issues, especially on the more complex tables. Using max-width
means that we don't need to negate anything. If we can find a clean way
to negate these styles, we can simplify things a bit. All demos now
work on IE9 and are solid.
Dialog: Make sure close button inherits header theme.

When the button is added to the dialog during _create(), the header is not yet enhanced, so getInheritedTheme() works incorrectly. OTOH, since the header is not enhanced, the button need not be enhanced during create either, since it will be enhanced later when the header is itself enhanced. The button only needs to be enhanced when the option is being set on-the-fly.
Fix another notice in dynamic-samples/category.php.

Fixes this errors:

PHP Notice:  Undefined variable: catgory_object in /var/lib/jenkins/jobs/jQuery Mobile Latest/workspace/compiled/demos/docs/pages/dynamic-samples/category.php on line 130

Follows-up cac203291eb9294a2be3f69ce0d5ae954e3a069d
Merge pull request #5319 from Krinkle/php-errors

Fix another Undefined variable in dynamic-samples/category.php.
Fix yet another notice in dynamic-samples/category.php.

Looks like every time we fix one, the noise reduces and clarifies
another one.

Fixes this error:

PHP Notice:  Undefined variable: category_object in /var/lib/jenkins/jobs/jQuery Mobile Latest/workspace/compiled/demos/docs/pages/dynamic-samples/category.php on line 130

Follows-up cac203291eb9294a2be3f69ce0d5ae954e3a069d
Merge pull request #5322 from Krinkle/php-errors

Fix yet another notice in dynamic-samples/category.php.
Scroll long source code inside the collapsible. Code cleanup.
Page: Attach handlers using ._on(). Helps fix #2215

When a page widget is destroyed on an element, the pagebeforehide and pagebeforeshow handlers must be removed, otherwise, if another page widget is instantiated on the same element later on, the handlers from the previous instance will be left around and so the new instance will have the two events handled twice.
Dialog: Attach pagebeforeshow handler using ._on(). Fixes #2215.

When a dialog widget is destroyed on an element, the pagebeforeshow handler must be removed, otherwise, if another dialog widget is instantiated on the same element later on, the handler from the previous instance will be left around and so the new instance will have the event handled twice.
Fix PHP error in forms-sample-response.php.

Entry from error_log:

PHP Notice:  Undefined index: shipping in /var/lib/jenkins/jobs/jQuery Mobile Latest/workspace/compiled/demos/docs/forms/forms-sample-response.php on line 34

Follows-up 5e5f9387bf4354f8d7c7f89de56d7d54dfb4c14b
Merge pull request #5326 from Krinkle/php-errors

Fix PHP error in forms-sample-response.php.
Improve performance of demo source code view.
Prevent page scroll while scrolling demo source code.
Syntax highlighter configuration.
Docs: minor correction to api/events (all together -> altogether)
Custom select: Must depend on navigation to open.