MAJOR UPDATE:
-Layout API changes: Layout extends Sizeable, Layout has two methods setMargin.
-OrderedLayout and GridLayout got two new mehtods: setSpacing and setComponentAlignment.
-Client-side layout implementations now mainly done using TABLE elements (changes to IOrderedLayout and IExpandLayout).
-IScrollTable initial height calculation modified (small fix, clientHeight -> offsetHeight).
-Some test modified to conform to new layout API.
-Small typo fixes in comments.
-OrderedLayout fix when changing orientation on the fly.
-Panel and TabSheet are no longer Layouts, only ComponentContainers.
-Refactored layout margins to use MarginInfo class, more readable, self-documenting code now.