Don't dispose the HttpClient

[MarcusOtter]

Is your feature request related to a problem? Please describe.
It's weird how the apod client will dispose of the HttpClient you give it when the apod client is disposed. In practice it means you shouldn't call dispose on the apodclient if you want to reuse the HttpClient.

Describe the feature you'd like
Don't default to creating an HttpClient, take it as a required parameter and make it non-disposable. Caller does the disposing.