Fix vibrator, which was not working on Android devices.

[ghost]

Fixes #501 #509

In this PR I implemented a solution considering the deprecations applied since API 26 (check https://developer.android.com/reference/android/os/Vibrator). In order to make the vibration work again, I had to first use jnius.cast with "android.os.Vibrator" and VIBRATOR_SERVICE.

Since API 26, the VIbrationEffect class admits different types of vibrations, but I just implemented https://developer.android.com/reference/android/os/VibrationEffect.html#createOneShot(long,%20int) and https://developer.android.com/reference/android/os/VibrationEffect.html#createWaveform(long[],%20int), otherwise I could break plyer's VIbrator API.

This PR has been already tested. Anyway, I invite you to try it and post the results.

[ghost]

@Zen-CODE This is ready to be checked.

[Zen-CODE]

Thanks for this. It's a nice PR, and I appreciate the consideration for backwards compatibility +1

[ghost]

You're welcome!

[tomgold182]

@Zen-CODE what about the fix to the camera module ? it is not working on android anymore

[tomgold182]

@franccisco Is there any way to use this important commit with buildozer without waiting for a new plyer version ?

[Zen-CODE]

@tomgold182 Yes. In your requirements, instead of just "plyer", point it to the github repo using the master branch. Google should tell you how to do that: it's just like a pip requirement.

With regards to the camera fix, that would be great. You are welcome to submit a PR fixing that.

[tomgold182]

@Zen-CODE Thank you for your response!
As for the camera fix, the is already a PR waiting :
#525

[Zen-CODE]

@tomgold182 Can you confirm that it works for you?

[tomgold182]

@Zen-CODE Will check soon and let you know.
Thanks!