remove unused seekbarpreference class and fix the one for the navbar

it wasn't saving the user adjust value and kept resetting to the previous
default on config changes and scrolling it off screen

PS2: factor out extraneous class.. convert string to parseInt yatta yatta
PS3: fix the XML classpath

Change-Id: Ia0fea6cf914204fcf2fc37483b846814963220c0
Merge "remove unused seekbarpreference class and fix the one for the navbar" into jb43