#11 Fallback to ACTION_GET_CONTENT if OPEN_DOCUMENT unsupported

[o3661606]

As I cannot simulate the case on phone, therefore I "force" it to run on Android 18 emulator by changing minSdk

Below is some log entries for your reference, doesn't know if the returned uri is an expected result.

D/FilePickerWritable( 2572): Got method call: openFilePicker
D/FilePickerWritable( 2572): Cannot launch file picker using Intent.ACTION_OPEN_DOCUMENT, falling back to Intent.ACTION_GET_CONTENT
D/FilePickerWritable( 2572): onActivityResult(40832, -1, content://media/external/../..../......)
D/FilePickerWritable( 2572): Got result content://media/external/../..../......