Avoid using floats due to issue on Exynos devices

[vanaf]

Fixes issue https://github.com/googlecreativelab/ar-drawing-java/issues/2

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[vanaf]

I signed it!

[googlebot]

CLAs look good, thanks!

[brijeshshah13]

Fixes #5 as well. @HalfdanJ I recommend you to merge this PR, as the app sometimes crashes due to the error mentioned in the logs of the issues.

[HalfdanJ]

Thanks!