Move all of midiplay into its subdir and add a Makefile for it, add header files as necessary.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@14841 a1c6a512-1295-4272-9138-f99709370657
diff --git a/apps/plugins/midi/SOURCES b/apps/plugins/midi/SOURCES
new file mode 100644
index 0000000..74c0bf1
--- /dev/null
+++ b/apps/plugins/midi/SOURCES
@@ -0,0 +1,6 @@
+midifile.c
+midiutil.c
+sequencer.c
+guspat.c
+synth.c
+midiplay.c