Fix compilation failure on latest rust-nightly

&[1u8, 2, 3, 4] seems to be of type &[u8, ..4] instead of type &[u8],
use [1u8, 2, 3, 4].as_slice() instead
Merge branch 'master' into box_inplace
Fix compilation failure on latest rust-nightly

&[1u8, 2, 3, 4] seems to be of type &[u8, ..4] instead of type &[u8],
use [1u8, 2, 3, 4].as_slice() instead
Add input length checks for seal/open_inplace

This is so that the slice_to calls in those functions won't call panic!
if the input is too short
Removed unused attributes

These attributes led to compiler warnings with the latest rust-compiler.
Merge branch 'master' into box_inplace