blowfish.rs fails to compile on nightly 1.6

[HybridEidolon]

Breaking change in derivations of Clone for arrays; see rust-lang/rust#30244.

Offending line:

rust-crypto/src/blowfish.rs

Line 13 in db7fe6c

s: [[u32; 256]; 4],

rust-lang/rust#30130 was reverted due to ICEs related to Copy on large arrays in rust-lang/rust#25733

Possible solution: use a pre-sized Vec i.e. vec![vec![0u32; 256]; 4] in Blowfish::new.

[Dr-Emann]

duplicate of #335