Revert "Sortable: Always set placeholder size when necessary. Fixes #8262 - jQuery UI 1.8.19 don't respect forcePlaceholderSize."

This reverts commit 4f19289c10e733a07cf60435c2e5df4ed2e23d37.
(cherry picked from commit 21df5c27e312c6e5fda66e602abefa51c484d676)
Revert "Sortable: modified the contents of placeholder to a single "&nbsp;". Fixed #8135 - sortable: Horizontal sortable shifts causes elements to shift down."

This reverts commit b6e1f25ab8c038306146a6ead041dc18bfb9e8c2.
(cherry picked from commit b38dd26da0a7297941839195ff75885d6ecc67d0)
Draggable: Don't run stop methods for elements that have been removed.  Fixed #8269 - Removing draggable element on drop : a(this).data("draggable") is undefined.
(cherry picked from commit 27d10235539e0f5baad6ee7e8d3d91cab65e2cfd)

Conflicts:

	ui/jquery.ui.draggable.js
Sortable: update placeholder when axis is x or y. Fixed #8274 - placeholder doesn't move when dragging outside of container element
(cherry picked from commit b8b0c528301ab2bfc49e36143a3c4f6451e58ccd)
Tagging the 1.8.20 release.
Updating the 1-8-stable version to 1.8.21pre
Datepicker range demo: Use public APIs. Fixes #8292 - Double Click on from date in Date range datepicker.
(cherry picked from commit f6c0b71ae9cbed55bdcfd8058a4c89fee0b4c068)
Sortable: Moved change of helper position css. Fixed #5321 – Helper in a bottom-positioned Sortable is positioned wrong on drag start.
(cherry picked from commit 32f356bbfa9a8f3b90b4e64331e9108b4d87a349)
Autocomplete combobox demo: Define this.wrapper for use inside destroy().
(cherry picked from commit c974d0fc69849d9e7854a532da01f00587d04527)
Effects: Check for anonymous content being exposed via document.activeElement. Fixes #8288 - Regression: jquery-ui animations focus fix causes Firefox Security Manager veto.
(cherry picked from commit a7e143b4fe395baeda297ea96ef39921ea7f5a5d)

Conflicts:

	ui/jquery.effects.core.js
Position: Patch .offset( fn ) setter for jQuery 1.3.2. Fixes #8254 - Position module throws uncaught exception on IE8 with jQuery 1.3.2.
Datepicker: Fixed Basque locale. Fixes #8318 - Datepicker i18n: Basque locale incorrect.
(cherry picked from commit 1304c50532b65738a7fc3c9deb3943f7de308539)
Autocomplete combobox demo: Add combobox-specific classes for styling. Fixes #8322 - Autocomplete: Combobox demo should not override .ui-button styles.
(cherry picked from commit 1b19121189356879ca39a19ba241a04ff4786b62)

Conflicts:

	demos/autocomplete/combobox.html
Sortable: calculating item positions on the fly and setting the direction variable when inserting an item into a different sortable. Fixed #8268 - Items may not be inserted into the correct position when dragged between connected sortables
(cherry picked from commit c42bdcecf825e295f483413f8d20b2079947faec)

Conflicts:

	ui/jquery.ui.sortable.js
Progressbar demo: Made animated background selector more specific. Fixes #8314 - Theme on animated progressbar remains the same.
(cherry picked from commit cb70a5e302aae16fa4b47454c1d7d5aca514bfb7)
Draggable: Apply ui-draggable-dragging class prior to calculating dimensions. Fixes #8349 - Draggable: Incorrect dimensions used if .ui-draggable-dragging changes dimensions
(cherry picked from commit a0c18ea25086ed07634baff5b4fea46e69aad38e)
Datepicker: Corrected language code for Georgian language according to ISO 639. Fixed #8356 - jquery.ui.datepicker-ge.js has wrong language code.
(cherry picked from commit 0bbad349b982839c607d7c16bf2e46a293532dee)
Build: Ask user to verify AUTHORS.txt is up to date before doing a release.
Datepicker: Changed Arabic dayNamesMin to one-letter strings. Fixes #8375 - Datepicker: Incorrect dayNamesMin for Arabic locale.

Before this change the minimal names for days of week were the same
as the long names. This caused the datepicker to be too wide.

The one-letter strings come from the CLDR:
http://unicode.org/repos/cldr-tmp/trunk/diff/summary/ar.html
(cherry picked from commit 8f42ab013469865ae790089717a56b6ca774dc75)
Tagging the 1.8.21 release.