Functional EditId3 and Layout (see description)

FileEditor
* Editing Id3 tags works now.
* (Android Manifest) Needed to add app permissions to be allowed to edit
external files.
Edit Id3
* Prepopulate the input fields with the existing data.
* Bug: Multiple selection prepop doesn't fill in data properly.
* Bug: Editing a file a second time will not show prepop information.
Layout
* Made EditId3 screen legible, removed overlapping and "hidden" input
text.
* Made layout dynamic in that if you move the parent item, the rest move
with it (don't use drag & drop GUI!)
* Makin' it purty.