A new option changes the "change_method" into the new
"change_method_prev". It switch to the previously used input method.
A long press on "change_method_prev" sends "change_method".
A new section is added in the settings and existing options are moved.
It allowed to modulate the repeat speed of some keys (arrow, backspace,
delete) by move the finger farther or closer to the key.
In practice, this wasn't pratical and doesn't seem popular. It is
removed in favor of a better mechanism for moving the cursor.
* Add option for keyboard opacity (transparency). Keyboard background, keys and pressed keys can be adjusted separately.
* Make the borders transparent as well
* Moved setAlphas outside drawKeyFrame to top of onDraw method
