Add InputStream access in addition to Bitmap access to returned image

[jfinkhaeuser]

When your goal in image picking isn't to display the image immediately, but to do something with it (e.g. upload somewhere), there's no need to use up all the memory for loading an image file into a Bitmap instance.

This is especially true as many APIs allow streaming access precisely to avoid huge memory overhead.

This addition returns an InputStream instead of a Bitmap (but is otherwise functionally equivalent). InputStream is what you can get from ContentResolver for e.g. gallery access, and from the temporary file written by the camera access, so makes for the best interface here.

[Mariovc]

Thank you for your contribution. Nice!