This change introduces,
- new attribute keyboardHeight to specify default keyboard height.
- new attribute maxKeyboardHeight to specify maximum keyboard height,
usually specified by percentage to the screen height.
- keyHeight attribute is obsoleted
- new attribute rowHeight to specify a row height, can be specifed as
percentage of the keyboard height. And verticalGap is included to
the row height (row height = key height + vertical gap).
Change-Id: I48a2f2661e8a91a998503a847437c1baf1de9b9c
