panic in user-provided `Endian` impl triggers double drop of T

Affected versions of the crate does not guard against panic from user-provided impl of Endian trait, which is a safe trait that users can implement.
If a user-provided implementation of the Endian trait panics, double-drop is triggered due to the duplicated ownership of T created by ptr::read().

Double-drop (or double free) can cause memory corruption in the heap.