Add logging to test alt handling

cc #93
diff --git a/src/input.rs b/src/input.rs
index 47ce52f..d6d597e 100644
--- a/src/input.rs
+++ b/src/input.rs
@@ -368,9 +368,11 @@
         // Didn't process a binding; print the provided character
         if let Some(mut string) = string {
             // from ST
+            println!("process_key got string={:?}, mods={:?}, key={:?}", string, mods, key);
             if string.len() == 1 && mods.contains(mods::ALT) {
                 string.insert(0, '\x1b');
             }
+            println!("process_key sending {:?}", string);
 
             self.ctx.notifier.notify(string.into_bytes());
             self.ctx.selection.clear();