Updated mediawiki/extensions
Project: mediawiki/extensions/Echo  acce7cc9fbd093ab1d6149df7156ed77837cbe9c

Hygiene: Alter how initialisation of the overlay works

Restructure code so MobileFrontend can make use of it
Kill ext.echo.desktop

Change-Id: I984373ba54206d447c54a435dbf60e8f6e814be1