Allow to decrypt while keeping the "DEC::..."

[c33s]

it would be handy for system which are working with IDE's and files are project bound, to have something like this:

eyaml decrypt --keep-tags filename.yaml

where the encrypted file is decrypted like its done with eyaml edit but without the editor overhead.

so the unencrypted file would be:

some_new_key: DEC::PKCS7[a new value to encrypt]!

the eyaml edit is too much bound to editors.

[c33s]

opened the ticket too fast, works with:

eyaml decrypt -e $file