Minor: Use template parameter default values for hb_prealloced_array_t
Minor: Use template parameter default values for OffsetTo
Minor: Introduce GenericOffset
Minor: Reorder template parameter order
Minor: Remove some GenericXXX templates
Minor: Remove GenericOffset
Minor: Remove LongOffsetArrayOf and LongOffsetLongArrayOf
Minor: Remove LongSortedArrayOf
Minor: Remove LongArrayOf
Minor
Minor: final bits of cleanup