Note: This is a breaking change

Authored-by: Dennis Leon <leonde@vmware.com>

- Useful by consumers providing their own Predicate to determine whether to retry or not

Authored-by: Dennis Leon <leonde@vmware.com>

… http retries

Authored-by: Dennis Leon <leonde@vmware.com>

- add test to assert behavior around using a transport.Wrapper results
in no additional wrapping such as retry is done.

refactoring

- add comments
- rename transport.Transport -> transport.Wrapper
- make transport package return transport.Wrapper

Authored-by: Dennis Leon <leonde@vmware.com>

- Consumers should construct a transport.Wrapper via constructor
transport.NewWithContext
- options retryBackoff and retryPredicate should only apply to http
errors and not lower level transport errors. (Consumers can still provide
a transport with the retry behavior they want)

Authored-by: Dennis Leon <leonde@vmware.com>