Small fixes in sample.
Add MathJax plugin to samples/index.html.
Changelog entry.
Merge branch 't/10664' into major
Remove semicolons before brackets in MathJax plugin.
Expose privates in a different way.
Display style does not have to be at the end.
Merge branch 't/10830' into major
jsLint fixes for MathJax plugin.
JSLint fixes.
Added missing changelog entries for #10659 (image2) and #9764 (widgets).
Renamed plugin languages to language, removed variable languagesButtonsGroup and used literal string instead.
Minor fixes.
Removed obsolete parentheses.

* Simplified code.
Fixed typo.
Merge branch 't/7987' into major
Documentation - fixes and part 1. of widgets system API.
Marked mathjax plugin as new in sample index.
Removed previously commented out selectionChange's errorProof definition.
Widgets API docs.