Use sequence<long> instead of UInt32Array
Make attributes nullable, to allow returning null value.
Minor wording fixes on inputMethodContext property.
Mention nullable attributes in Changes.txt.
Fix off-by-one error in the desctiption of selectionEnd.
Modify wording of "life of InputMethodContext" text.
Fixed a bug (input and suggest was opposite) in example1 code, and
added some comments.
Add example2 code (drawing composition text).
Mention a new example (drawing composition text)
Add setCaretRectangle() call in example2.
Reorder changes.