[build] Attempt to fix flickering test.
- Implemented inside the DatePicker constructor a wait for the popup to show so that clients don't have to manually call the wait.
- This also inroduces the same pattern we have for pages, that is to first make the UI available (i.e. click to display the date picker) and then call the constructor to start using it, never the other way around.
XWIKI-11314: Changing the current language from the UI does not preserve the query string of the current URL.
XWIKI-10333: Manage listed applications in Applications Panel.
XWIKI-11300: Glyphicons are not loaded on a subwiki using a custom skin based on Flamingo and stored in the main wiki.
[release] Updated translations.
XWIKI-11337: Add ability to export several pages as XAR, using a custom export URL
Merge branch 'master' of github.com:xwiki/xwiki-platform into feature-tree