Minor corrections of Shared Spaces API docs.
Add note that change-event is only fired in wysiwyg-mode

- see ticket #12031
Improved editor#change event documentation.
Undo plugin API docs corrections.
Toolbar plugin API docs corrected.
Added Bender to dev project.
Update package.json.
Added node_modules in any folder to .gitignore.
Added 'tests', 'package.json', 'bender.js' and 'node_modules' to the build ignore list.
Added tests.
We use tabs not spaces.
Filled package.json with more information.
Fixed ticket tests.
Added bender logs to ignored files.
Fixed test core/ckeditor/basepath.
Strict mode in bender config.
Fixed part plugins tests.
Fixed core tests.
Fixed tests for html data processor.
tools.focus apparently does not run tests in test case context.