Make widgets visible in MonoBook

Bug: 64658
Updated release notes
Merge pull request #52 from wmde/monobook

Make widgets visible in MonoBook
Comma expression by mistake
Remove duplicate array key
Merge pull request #54 from wmde/duplicate-key

Remove duplicate array key
Merge pull request #53 from wmde/comma

Comma expression by mistake
Update jshint config

The empty .jshintignore is necessary so that jshint does not pick up
core's jshintignore (which ignores all files in extensions).
Factor inputextender and content out of time and globecoordinate experts

This introduces ExpertExtender with some modules. It makes it possible to reuse
the inputextender in other experts, like quantity or monolingualtext.