fix #754 make TemplateContext.getDomId private

Close #793.
feat #786 Updating the skinnable properties of Icon widget

Making the background-size, background-color, border and border-radius available through the skin

Close #786
doc Fix missing doc, wrong types, typos

1) make type="implements Foo" notation consistent with the other classes.
Search for `@type(.*)\.I[A-Z](.*)` in the repo, we never precede it with the Object

2) missing `$urlService` in the API docs while `$requestHandler` is there

3) typos