moved some Intent extra constants into more appropriate places, some basic preparations to test thread-pausing during decryption/encryption to deal with certain situations, mainly an unknown signature key

src/org/thialfihar/android/apg/PausableThread.java

@@ -0,0 +1,35 @@
+package org.thialfihar.android.apg;
+
+public class PausableThread extends Thread {
+    private boolean mPaused = false;
+
+    public PausableThread(Runnable runnable) {
+        super(runnable);
+    }
+
+    public void pause() {
+        synchronized (this) {
+            mPaused = true;
+            while (mPaused) {
+                try {
+                    wait();
+                } catch (InterruptedException e) {
+                    // ignore
+                }
+            }
+        }
+    }
+
+    public void unpause() {
+        synchronized (this) {
+           mPaused = false;
+           notify();
+        }
+    }
+
+    public boolean isPaused() {
+        synchronized (this) {
+            return mPaused;
+        }
+    }
+}