Touch zone decouples screen size from gesture event registration.
The win here is each individual widget does not need to update
gesture range on screen rotate/resize anymore.
Another advantage is we now have a centralized ordered array to handle
all registered touch event listeners, makes it much easier to resolve
gesture range conflicts between multiple widgets.
This patch also includes the following changes:
* migrate readerpaging to use readerui's touch zone
* migrate readerfooter to use readerui's touch zone
* move inverse read direction setting to touch menu's setting tab
* moved kobolight widget from readerview into readerui
* various dead code cleanups and comments
