TWRP-ify AOSP code

Pull in most TWRP sources
Stub out partition management code
Make it compile -- probably will not boot
Kind of a mess but have to start somewhere
diff --git a/gui/remaining.txt b/gui/remaining.txt
new file mode 100644
index 0000000..298ee90
--- /dev/null
+++ b/gui/remaining.txt
@@ -0,0 +1,4 @@
+* Confirmation of action
+* Multi-String Variables
+* String Box
+