GH-145 Adjust Package References for Android

[jamesmontemagno]

Description of Change

Match Xamarin.Forms for Android NuGet Libraries.
Can no longer use fancy Android 8 Features, so if def them for now.

Bugs Fixed

• Related to issue Issues Installing NuGet with Forms Templates #145

Provide links to issues here. Ensure that a GitHub issue was created for your feature or bug fix before sending PR.

API Changes

Changed:

• Vibrate will always fall back to classic.

PR Checklist

• Has tests (if omitted, state reason in description)
• Has samples (if omitted, state reason in description)
• Rebased on top of master at time of PR
• Changes adhere to coding standard
• Updated documentation (see walkthrough)

[mattleibow]

Sad, but real. 😭

[mattleibow]

We could also include BOTH 7.1 and 8.0... A bit more work, but then we stay perfect.

[jamesmontemagno]

We thought about both 7.1 and 8.0, but they would still technically both need 25.X support libraries for compat reasons with Forms.

@Redth thoughts on doing both 7.1 and 8.0 for API surface?

[Redth]

technically we could compile against 8.0 still and ship a nuget with 7.1 with the 8.0 compiled dll as long as we did runtime checks around any 8.0 api's used. I'm guessing the /t:Pack won't allow this very easily...

I do not think we should ship multi targeted builds for both 7.1 and 8.0 however.