standard mismatch: ext-parameter shall be placed before mac-parameter

[swk1986]

According to the documentation the ext-parameter - if present - shall be placed before the mac parameter.

The hawk parameters shall be ordered in this sequence:

1. id
2. ts
3. nonce
4. hash
5. ext
6. mac

According to this sourcefile the order differs:

1. id
2. ts
3. nonce
4. mac
5. ext
6. hash

I found this issue when working with an hawk-protected api which didn't accept incorrect ordered parameters. It would be stunning if you could fix this issue.