Merge pull request #803 from coffeemakr/bugfix-play-from-sdcard

[WIP] Add root-path /storage (fixes #707)

app/src/main/res/xml/provider_paths.xml

@@ -1,4 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <paths xmlns:android="http://schemas.android.com/apk/res/android">
     <external-path name="external_files" path="."/>
+    <root-path name="external_files" path="/storage/" />
 </paths>