Support withCredentials attribute for XHR requests (Chrome 3+, Firefox 3.5+, Opera12+, Safari 4+, Internet Explorer 10+)

Review at http://gwt-code-reviews.appspot.com/1879804

Review by: cromwellian@google.com
Fix typo in withCredentials statement

Review by: cromwellian@google.com
Inline javascript:'' within NamedFrame's internal SafeHtmlTemplate

This prevents the URI from being sanitized by the SafeHtmlTemplates
generator. This is a regression from GWT 2.4, introduced at r10801.

Fixes issue 7909

Change-Id: Ic96c36b3f98705fff8a7638c8975901c50856951
Review-Link: https://gwt-review.googlesource.com/#/c/1800/

Review by: goktug@google.com
Updates ICU4J from 4.4.2 to 50.1.1

GWT uses ICU4J for formatting dates and times in translated messages.
See com.google.gwt.i18n.rebind.DateTimePatternGenerator.

For example, the token "{0,localdatetime:tz=$tz,yMd hms}" was previously rendered as
"2/1/2010 7:04:05 PM" in English and is now rendered as "2/1/2010, 7:04:05 PM"
(with an extra comma). Other major changes to ICU4J since 4.4.2 are available from
this web page: http://site.icu-project.org/download

Contributed by: jat@jaet.org
Change-Id: I75c9e0e07c4d29a75573701a676a19d6e83b91d9
Review-Link: https://gwt-review.googlesource.com/#/c/1700/