Fix bug of incorrectly suppressed errors in CLI

Fixes grnet/kamaki#56

The bug is limited in "kamaki create network"
Stop using 400 error code as equivalent to 404

Fixes grnet/kamaki#57

In some cases, the error code 400 was placed side by side with 404
so that kamaki.cli understood the former as a "NOT FOUND" error.
Set default logger to astakosclient.AstakosClient

Fixes grnet/kamaki#58

This bug fix refers to the LoggedAstakosClient wrapper.
The class AstakosClient is not forced to use a default logger.
Show the correct name when switching kamaki users

Fixes grnet/kamaki#66