Fix IE11 display issue

src/signature.js

@@ -14,7 +14,7 @@ angular.module('signature').directive('signaturePad', ['$interval', '$timeout',
     return {
       restrict: 'EA',
       replace: true,
-      template: '<div class="signature" style="width: 100%; max-width:{{width}}px; height: 100%; max-height:{{height}}px;"><canvas style="display: block; margin: 0 auto;" ng-mouseup="onMouseup()" ng-mousedown="notifyDrawing({ drawing: true })"></canvas></div>',
+      template: '<div class="signature" style="width: 100%; height: 100%" ng-style="{\'max-width\': width + \'px\', \'max-height\':height + \'px\'}"><canvas style="display: block; margin: 0 auto;" ng-mouseup="onMouseup()" ng-mousedown="notifyDrawing({ drawing: true })"></canvas></div>',
       scope: {
         accept: '=?',
         clear: '=?',