Status Codes

[OpenTransact] should use existing HTTP status codes as much as possible. Here is a preliminary list:

Code	HTTP meaning	OpenTransact meaning
200	Success	Transfer went through
400	Bad request	Request is missing opentransact required fields of to and/or amount. Also if errors in any fields.
404	Not found	Currency or subcurrency (Holds etc) does not exist
403	Forbidden	Insufficient funds. 403 says the reason can be in the response body. JSON anyone?
410	Gone	A transfer is made to an expired asset (eg a hold)

Any others? Please update and comment.