jquery.tablesorter: Add missing dependency on jquery.mwExtension

Partial backport of e9186da84.

Bug: 52606
Change-Id: I6429a233b8679689255b5a952c5496d43ee341fa
Purge upstream caches when deleting file assets.

Inform upstream caches when a file asset is deleted by calling
SquidUpdate::purge(). This helps prevent unintentional information leakage in
the event that the asset is being deleted for reasons of license or content.

Bug: 51064
Change-Id: Ibf57e8f32d7dd04b8508a69706be5a40b49e5abd
Release note update for bug 51064.

Change-Id: Ie9387abbf39d41b3376286a18456fd2c83a58df8
Merge "Release note update for bug 51064." into REL1_19
(bug 50078) Allow a string other than '*' as condition for DatabaseBase::delete()

Currently, either '*' is given as condition meaning "everything" or an array must
be passed since DatabaseBase::makeList() requires an array. Now the parameter is
consistent with one of other similar methods, since a string will be handled
correctly.

Bug: 50078
Change-Id: Id5a8220d21245669f1091a3b5ed1def65b22d375
(cherry picked from commit b18770232c679482e0c7bf775b84eda5f7f3b782)
SECURITY: Fix extension detection with 2 .'s

Fix IE6 extension detection, to prevent XSS in the API response.

Bug: 52746
Change-Id: If58a81b62209b36bd143a1766a8a20c9c34dbe3b
SECURITY: Prevent tokens in jsonp mode

Add checks to token-returning functions to prevent returning tokens in
jsonp mode. This affects action=login, action=block, action=unblock, and
action=query&list=deletedrevs.

Bug: 49090
Change-Id: Ibeaa5c72d8084585092b15935a3f5709104bf7f7
SECURITY: Sanitize ResourceLoader exception messages

Prevent path disclosure when $wgShowExceptionDetails is false

Bug: 52746
Change-Id: Ia14ae21972192d291cb86dce65568e9e8b4674f7
Update Releasenotes and version number for 1.19.8

Change-Id: I6b1df7c8a3ee91f2aaf6c14740028c76988ed602
Merge branch 'REL1_19' of https://gerrit.wikimedia.org/r/p/mediawiki/core into REL1_19