avoid deprecated lifecycles

Is this a bug report?

YES

It would be very nice if you could implement functions to check if flashlight is enabled or not, currently we can only set it to enabled or disabled.

I came to your repo through a StackOverflow answer.
You're CMakeLists.txt file is using environment variables (OpenCV_LIBS in particular).
It would be nice to include the expected variables with their values.
It would save time to those people like me not very accustomed to OpenCV.
Thanks in advance.

I am using the version 0.0.9 of the plugin (after the redesign from 0.0.8).
Please notice that the documentation says that the method takePicture() requires a callback which takes a string with the image as a callback parameter, However, I am getting an array with a single string element back (instead of just a string). You should fix the doc or the code.

P.S.
Version 0.0.8 generated two ima