move UniqueId into its own module
remove unnecessary imports
remove unnecessary imports
move sectorLength as a polymorphic number in its own module
define addrToSector
add a sectorPerBlock helper
in appendEmptyBlock return the new physical sector allocated
don't use fromIntegral in front of already polymorphic sectorLength
remove unsafeLookupBat in favor of lookupBat.

also make it returns a Maybe all the time
slightly better lookupOrCreate algorithm.

this doesn't query the Bat twice, but use the new returned value in appendEmptyBlock.
add a function to iterate over every sector in a block.
remove unnecessary bindings, and remove shadowing (length, tail, ..)
add some signature
separate header in its own module, and remove 1 orphan instance
add some signature
add an option to dump the bat, instead of doing it all the time.
add a sized class
move batmap into its own module
sectorPerTrack is polymorphic already, no need for fromIntegral
don't do any batmap stuff