* Consolidate crypto functionality in `ethcore-crypto`.
- Move `ecdh`/`ecies` modules to `ethkey`.
- Refactor `ethcore-crypto` to use file per module.
- Replace `subtle` with `ethcore_crypto::is_equal`.
- Add `aes_gcm` module to `ethcore-crypto`.
* Rename `aes::{encrypt,decrypt,decrypt_cbc}` ...
... to `aes::{encrypt_128_ctr,decrypt_128_ctr,decrypt_128_cbc}`.
* rpc: generate new account id for imported wallets
* ethstore: handle duplicate wallet filenames
* ethstore: simplify deduplication of wallet file names
* ethstore: do not dedup wallet filenames on update
* ethstore: fix minor grumbles
* created the dir crate in util
* moved code from ethstore/src/dir/paths.rs to dir crate
* rename dir module in ethstore to accounts_dir to distinguish it
from the dir crate
* changes after @tomusdrw on #6952
