Fix EZP-23301: Upgrade to YUI 3.17.2

JIRA: https://jira.ez.no/browse/EZP-23301 (actually to fix https://jira.ez.no/browse/EZP-23193 in PlatformUI)

# Description

Ironically, this upgrade is needed to fix a rendering issue in PlatformUI when using Chrome 36 and up. This happens because there was a bug in YUI that is triggered by the fact that Chrome 36 now uses an *unprefixed* version of the `transform` CSS style.

See also:

* https://github.com/ezsystems/PlatformUIBundle/pull/107
* https://github.com/ezsystems/DemoBundle/pull/111

# Tests

manual tests + unit tests in PlatformUI