adding touch elt specific methods

Author: Lauren McCarthy

lib/p5.js

@@ -117,7 +117,8 @@ var core = function (require, shim, constants) {
         'touchstart': null,
         'touchmove': null,
         'touchend': null,
-        'resize': null
+        'resize': null,
+        'blur': null
       };
       this._loadingScreenId = 'p5_loading';
       this._start = function () {
@@ -3121,6 +3122,9 @@ var inputkeyboard = function (require, core) {
         }
       }
     };
+    p5.prototype.onblur = function (e) {
+      downKeys = {};
+    };
     p5.prototype.keyIsDown = function (code) {
       return downKeys[code];
     };