normalize binding addresses

[ekoby]

• allow more flexible configuration of bindings
• update ziti-sdk

Binding addresses can be specified via tuple, string, or int, such as the following binding addresses are considered the same:

• ('0.0.0.0', 1080)
• ('', 1080)
• '0.0.0.0:1080'
• ':1080'
• 1080

fixes #44