Remove the offset arguments from ctypes_memcpy.
Remove the offset argument to ctypes_read.
Remove offset arguments from ctypes_read_pointer and ctypes_write_pointer.
Remove the offset argument from ctypes_write.
Remove the offset argument from Ctypes_bigarray.view and supporting stubs.
Remove offset argument from Memory_stubs.string_of_array.
Remove offset argument to ctypes_string_of_cstring.