Bug fixed: now any dimension works

There was a problem with definition of array that stores rings data,
rows were mixed with cols. Now it works for any dimension preset (8x1,
1x16, 4x3 etc.)

Also shrunk touch-active area over every ring from 30 px to 26 px wide
rectangle. It is still OK and allows to sneak between rings in arrays
like 4x4.
Changed struct name