Handle runtime permissions when checking hardware support

[lkorth]

Return true for CardIOActivity#canReadCardWithCamera when camera cannot be access on API >= 23.

Fixes card-io/card.io-Android-SDK#136

[braebot]

Are we sure there isn't another error path that should be considered?

[braebot]

Thanks for the PR! Did you happen to look if the camera2 APIs would help, or is it just another way of getting the same information?

[lkorth]

I'd have to try it out, it looks like CameraManager#getCameraCharacteristics would provide the information needed, but it's unclear if it will work before obtaining permission.

[lkorth]

Checking camera characteristics does work without permission, however it requires a Context. This would require a breaking change to CardIOActivity#canReadCardWithCamera to take a Context.

[braebot]

Thanks @lkorth! We'd have to add a new method to take the context, while leaving the old one with this hack.

That being the case, I'll merge this, and leave the new method as a future enhancement.