Use and forward returntoquery parameter in Special:ChangePassword

Refactored the generation of hidden fields so that the returnto
and returntoquery only get added to the output if they actually
were provided in the request.

Change-Id: I144f04bec2fdd0947b5d206684d9c63a3d868168
Avoid Jenkins' CodeSniffer warnings for Userlogin

Change property declarations from "var" to "public". This eliminates the
 46 | ERROR | The var keyword must not be used to declare a property
warnings from Jenkins CI, e.g.
https://integration.mediawiki.org/ci/job/mediawiki-core-phpcs-HEAD/1565/console

http://php.net/manual/en/language.oop5.properties.php says
  "If you declare a property using var instead of one of public,
protected, or private, then PHP 5 will treat the property as if it had
been declared as public."
, so this should be a no-op.

Change-Id: I754ccea018f95421bfe3f7b04e3ab3a6d9b407e3
(bug 44459) Implement mw.message.text():

* Change default message format in mediawiki.js from plain to text (this includes behavior of mw.msg shorthand).
* Code changes are primarily in jqueryMsg, with minor supporting changes in mediawiki.
* Organize tests by public entrypoint (mediawiki or mediawiki.jqueryMsg).
* Additional tests and assertions for all public entry points, for new and existing behavior.
* Convenience test assertion methods
* Add explanatory comments for new and existing code.
* Add setting to jqueryMsg for format, defaulting to parse, to preserve existing behavior for direct callers to jqueryMsg's public API.
* Since there are now two ways of constructing the abstract syntax tree, add a new parameter to the cache's key scheme.
* Minor formatting

Change-Id: I0d220692262356a12e2f1c0ce30cf6f090428332
Merge "Use and forward returntoquery parameter in Special:ChangePassword"