Udsoncan

**Bugfix**
- Fixed 50 : Correctly encode filename length on 16bits instead of 8bits in RequestFileTransfer

**New feature**
- 49 : Security level now passed to the security algorithm when using ``client.unlock_security_access``. For backward compatibility, parameters are now given as named parameter. Only the parameters present in the algorithm signature will be passed. See the below snippet of code

algo_params = {}
try:
algo_args = self.config['security_algo'].__code__.co_varnames[:self.config['security_algo'].__code__.co_argcount]

if 'seed' in algo_args:
algo_params['seed'] = seed
if 'level' in algo_args:
algo_params['level'] = level
if 'params' in algo_args:
algo_params['params'] = params
except:
algo_params = {'seed':seed, 'params' : params, 'level' : level}

key = self.config['security_algo'].__call__(**algo_params)

47 - Now support RequestFileTransfer service

New feature (45). Allow the user to make a DidCodec that read a whole payload even if not dictated by ISO-14229.

New feature:
- Resolved 37 - Now possible to use ``client.payload_override`` to send arbitrary payloads and still take advantage of the client capacity of analyzing a malformed response. See https://udsoncan.readthedocs.io/en/latest/udsoncan/client.html#overriding-the-output

Bug fix
- 22 : Trying to use a closed connection will trigger the right Exception

Enhancement
- 29 : Now possible to use write_data_by_identifier with multiple values without specifying a custom codec
- 35 : Indentation switched to spaces instead of tabs
- Fixed several typos or erroneous error messages