Merge branch '103-disable-chalkboard-key-bindings-if-not-needed' into 'master'

Resolve "Disable Chalkboard key bindings if not needed"

Closes #103

See merge request decker/decker!40

resource/template/deck.html

@@ -292,12 +292,14 @@ $endif$
         keyboard: {
             40: function() { Reveal.next(); },                       // up:   next slide
             38: function() { Reveal.prev(); },                       // down: prev slide
+$if(chalkboard)$
             67: function() { window.RevealChalkboard.toggleNotesCanvas() }, // c: draw on slides
             84: function() { window.RevealChalkboard.toggleChalkboard() },  // t: draw on blackboard
             8:  function() { window.RevealChalkboard.clear() },             // BACKSPACE: clear chalkboard
             46: function() { window.RevealChalkboard.resetSlide() },             // DELETE: reset chalkboard
             68: function() { window.RevealChalkboard.downloadData() },          // d: downlad chalkboard drawing
             90: function() { window.RevealChalkboard.drawUndo() } ,         // z: undo last stroke
+$endif$
         },
       });
     </script>