Fix the key counting

Bail out if the key did NOT toggle on, instead of bailing out only if it did.
This addresses the key count computation part of #1. (Shifting looks fine, after
this change)

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>

src/Akela/Heatmap.cpp

@@ -85,7 +85,7 @@ namespace Akela {
       return mappedKey;
 
     // if the key is not toggled on, return.
-    if (key_toggled_on (keyState))
+    if (!key_toggled_on (keyState))
       return mappedKey;
 
     totalKeys++;